CoChat
Sign Up
Cited by 124Non-Invasive Vital Sign MonitoringHemodynamic Monitoring and TherapyOptical Imaging and Spectroscopy Techniques

Skin pigmentation influence on pulse oximetry accuracy: a systematic review and bibliometric analysis

Open access
Cabanas, Ana M., Fuentes-Guajardo, Macarena, Latorre, Katina, León, Dayneri, Martín-Escudero, Pilar·2022·Sensors
DOI 10.3390/s22093402PMC PMC9102088
Open this paper in CoChat — free accountOpen PDF

Abstract

Nowadays, pulse oximetry has become the standard in primary and intensive care units, especially as a triage tool during the current COVID-19 pandemic. Hence, a deeper understanding of the measurement errors that can affect precise readings is a key element in clinical decision-making. Several factors may influence the accuracy of pulse oximetry, such as skin color, body temperature, altitude, or patient movement. The skin pigmentation effect on pulse oximetry accuracy has long been studied reporting some contradictory conclusions. Recent studies have shown a positive bias in oxygen saturation measurements in patients with darkly pigmented skin, particularly under low saturation conditions. This review aims to study the literature that assesses the influence of skin pigmentation on the accuracy of these devices. We employed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to conduct a systematic review retrospectively since February 2022 using WOS, PubMed, and Scopus databases. We found 99 unique references, of which only 41 satisfied the established inclusion criteria. A bibliometric and scientometrics approach was performed to examine the outcomes of an exhaustive survey of the thematic content and trending topics.

AI snapshot

Written from the paper’s full text.

TL;DR

This PRISMA systematic review and bibliometric analysis of 41 studies (from 99 unique references) finds that pulse oximetry often overestimates oxygen saturation in dark-skinned patients, especially at low saturation, increasing occult hypoxemia risk. It also documents heterogeneous skin-pigmentation classification and risk-of-bias concerns across the literature.

Key findings

  • The review included 41 studies from 31 sources published between 1976 and 2022; among 11/35 studies at low risk of bias, 8/11 (72.73%) reported inaccuracies related to skin pigmentation, while 3/11 (27.27%) reported no demonstrable loss of accuracy.
  • Overestimations in dark-skinned patients were reported especially at low saturation: Feiner et al. found bias up to 8% at lower saturation, Bickler et al. found overestimation increasing linearly as SpO2 decreased, and Sjoding et al. found dark-skinned patients with SpO2 92–96% had arterial oxygen saturation <88% 11.7% of the time versus 3.6% in light-skinned patients (3 times higher).
  • Henry et al. reported SpO2 overestimating arterial blood gas-derived oxygen saturation by 1.57% on average, and Wiles et al. reported biases of 0.28%, −0.33%, and −0.75% for “White,” “Asian,” and “Black” patients, respectively.
  • Skin pigmentation was classified by Fitzpatrick scale in 6/37 studies (16.21%), Munsell scale in 4/37 (10.81%), EEL reflectance spectrophotometer in 1 (2.70%), ancestry descriptors in 11 (29.73%), and other subjective scales in 13 (35.14%).

Methods

  • PRISMA-based retrospective systematic review of PubMed, Web of Science, and Scopus from January 1975 to February 2022, using PICO-based research questions; 99 unique references were found and 41 satisfied inclusion criteria.
  • Bibliometric and scientometric analysis used Bibliometrix R-package/Biblioshiny and VOSviewer for keyword co-occurrence and cluster analysis; extracted data included author, year, journal, citations, author keywords, and research outputs.
  • Risk of bias was assessed with QUADAS-2 for 35/41 studies, excluding reviews, letters, and studies lacking required clinical/experimental procedure or data; robvis was used for visualization.

Limitations

  • Stated: there is no standard risk-of-bias tool for methods-comparison studies, so QUADAS-2 was used; many included studies classified skin pigmentation by unstandardized or qualitative judgments such as “dark,” “black,” “light,” or “white,” and some older negative studies may be misleading due to small dark-skinned samples or weak pigmentation correlation.
  • Stated: most pulse oximeters have been calibrated using light-skinned individuals, not all studies reported the selected characteristics, and more studies with clinical/patient-reported data and standardized skin pigmentation scales are required.
  • Evident: as a systematic review and bibliometric analysis, the paper does not pool effect sizes or perform a meta-analysis of accuracy across studies; its conclusions rely on qualitative synthesis of heterogeneous designs, populations, and oximeter models.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/s22093402

Cites

107 of 107 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 154 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    9/35 studies (25.71%) were at high risk of bias for one domain.

    “We found 9/35 studies (25.71%) to be at high risk of bias for one domain [17,21,44,45,51,79,82,87,88].”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    6 studies were in both groups: at high risk of bias for one domain and unclear risk of bias for at least two domains.

    “We also found that 6 of these studies were in both groups (at high risk of bias for one domain and unclear risk of bias for at least two domains) [17,44,79,82,87,88].”
    Quote in the paperNot a substantial claim
  • Findingown data

    The review identified 41 studies that fulfilled the inclusion criteria, from 31 different sources between 1976 and 2022.

    “We identified 41 studies that fulfilled the inclusion criteria from 31 different sources between 1976 and 2022.”
    • Also stated in: § Abstract · plain
      “of which only 41 satisfied the established inclusion criteria”
    Quote in the paperNot a substantial claim
  • Findingcitation

    Among the 11/35 low risk studies, 3/11 (27.27%) reported no demonstrable loss of accuracy caused by skin pigmentation.

    “3/11 (27.27%) reported no demonstrable loss of accuracy caused by skin pigmentation [46,48,70]”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [46] Bothma, 1996, Accuracy of pulse oximetry in pigmented patients, S. Afr. Med. J.

      Not checked in the free run.

    • cites [48] Foglia, 2017, The Effect of Skin Pigmentation on the Accuracy of Pulse Oximetry in Infants with Hypoxemia, J. Pediatr. source

      Not checked in the free run.

    • cites [70] Allado, 2021, Innovative measurement of routine physiological variables (heart rate, respiratory rate and oxygen saturation) using a remote photoplethysmography imaging system: A prospective comparative trial protocol, BMJ Open source

      Not checked in the free run.

  • Findingown data

    11/35 (31.43%) studies were at low risk of bias for at least three domains.

    “Finally, 11/35 (31.43%) studies were found to be at low risk of bias for at least three domains [23,38,46,48,69,70,71,77,78,84,89].”
    Quote in the paperNot a substantial claim
  • May combine two claims. 39
  • Classified as probably not a substantial claim. 28

  • May combine two claims.

    Findingown data

    6 of the 41 references studied in this review examined the performance of pulse oximetry during the COVID-19 pandemic, which is 50% of the references published since 2019.

    “We found that 6 of the 41 references studied in this review examined the performance of pulse oximetry during the COVID-19 pandemic [17,30,50,51,69,71], that is the 50% of the references published since 2019.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The three most influential papers were M. Kumar et al. with 236 TC and an average of 29.50 cites per year, Y. Mendelson et al. with 181 TC and an average of 5.17 cites per year, and A.C. Ralston et al. with 149 TC and an average of 4.66 cites per year.

    “The three most influential papers were M. Kumar et al. [78] with 236 TC and an average of 29.50 cites per year, Y. Mendelson et al. [21] with 181 TC and an average of 5.17 cites per year, and A.C. Ralston et al. [86] with 149 TC and an average of 4.66 cites per year.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Two prominent peaks in 2015 and 2020 correspond to M. Kumar et al. and M.W. Sjoding et al. with 29.50 and 37.00 TC per year, respectively.

    “Two prominent peaks in 2015 and 2020 are observed, corresponding to the references of M. Kumar et al. [78] and M.W. Sjoding et al. [50] with 29.50 and 37.00 TC¯ per year, respectively.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    35 of 41 studies were considered for risk of bias assessment.

    “We have considered 35/41 studies to perform risk of bias assessment of the individual studies shown in Figure 2.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    The principal reasons for exclusion were studies not focused on humans (5), skin pigmentation influence not evaluated (4), and oxygen saturation not evaluated (4).

    “The principal reasons for exclusion were: studies that did not focus on humans (5); skin pigmentation influence not evaluated (4); oxygen saturation not evaluated (4).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Major issues for unclear risk domains were possible bias in interpretation or conduction of the reference standard, and flow and timing in terms of patient flow and all patients receiving the same reference standard.

    “The major issues about these domains were related to possible bias about the interpretation or conduction of the reference standard, and about flow and timing in terms of patient flow and all patients receiving the same reference standard.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The most cited reference within the selection was P.E. Bickler et al. with 10 LC and a LC/TC ratio of 7.63%.

    “However, the most cited reference within our selection was P.E. Bickler et al. [23] with 10 LC and a LC/TC ratio of 7.63%.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    After title and abstract examination, 54 references were potentially appropriate for full-text reading.

    “After titles and abstract examination, 54 references were potentially appropriate for full-text reading.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    1/12 (8.33%) assessed that further studies with other clinical and patient-reported data are required to understand the effects of skin pigmentation on accuracy.

    “1/12 (8.33%) assessed that further studies with other clinical and patient-reported data are required to understand the effects of skin pigmentation on the accuracy [77]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [77] Sanyal, 2018, Algorithms for Monitoring Heart Rate and Respiratory Rate From the Video of a User’s Face, IEEE J. Transl. Eng. Health Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The search identified 99 unique references.

    “We found 99 unique references, of which only 41 satisfied the established inclusion criteria.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    M.W. Sjoding et al. has recently attracted much attention with 111 TC in the last two years.

    “Let us remark that the reference by M.W. Sjoding et al. has recently attracted much attention with 111 TC in the last two years.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Objective scales such as the Fitzpatrick Skin Pigmentation (FSP) scale or the Munsell scale were used by 6/37 studies (16.21%) and 4/37 studies (10.81%), respectively.

    “We find that objective scales such as the Fitzpatrick Skin Pigmentation (FSP) scale or the Munsell scale were used by 6/37 studies (16.21%) [61,69,70,71,76,77] and 4/37 studies (10.81%) [47,48,74,89], respectively.”
    Quote in the paperNot a substantial claim0 of 10 sources checked
    • cites [61] Shi, C., Goodall, M., Dumville, J., Hill, J.E., Norman, G., Hamer, O., Clegg, A., Watkins, C.L., Georgiou, G., and Alexander Hodkinson, A. (2022). Article The effects of skin pigmentation on the accuracy of pulse oximetry in measuring oxygen saturation: A systematic review and meta-analysis The effects of skin pigmentation on the accuracy of pulse and meta-analysis. PLoS Med. source

      Not checked in the free run.

    • cites [69] Stell, 2022, Exploring the impact of pulse oximeter selection within the COVID-19 home-use pulse oximetry pathways, BMJ Open Respir. Res.

      Not checked in the free run.

    • cites [70] Allado, 2021, Innovative measurement of routine physiological variables (heart rate, respiratory rate and oxygen saturation) using a remote photoplethysmography imaging system: A prospective comparative trial protocol, BMJ Open source

      Not checked in the free run.

    • cites [71] Harskamp, 2021, Performance of popular pulse oximeters compared with simultaneous arterial oxygen saturation or clinical-grade pulse oximetry: A cross-sectional validation study in intensive care patients, BMJ Open Respir. Res.

      Not checked in the free run.

    • cites [76] Ebmeier, 2018, A Two Centre Observational Study of Simultaneous Pulse Oximetry and Arterial Oxygen Saturation Recordings in Intensive Care Unit Patients, Anaesth. Intensive Care source

      Not checked in the free run.

    • cites [77] Sanyal, 2018, Algorithms for Monitoring Heart Rate and Respiratory Rate From the Video of a User’s Face, IEEE J. Transl. Eng. Health Med. source

      Not checked in the free run.

    • cites [47] Adler, 1998, Effect of skin pigmentation on pulse oximetry accuracy in the emergency department, Acad. Emerg. Med. Off. J. Soc. Acad. Emerg. Med. source

      Not checked in the free run.

    • cites [48] Foglia, 2017, The Effect of Skin Pigmentation on the Accuracy of Pulse Oximetry in Infants with Hypoxemia, J. Pediatr. source

      Not checked in the free run.

    • cites [74] Poets, 2019, Noninvasive Monitoring and Assessment of Oxygenation in Infants, Clin. Perinatol. source

      Not checked in the free run.

    • cites [89] Ries, 1989, Skin color and ear oximetry, Chest source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The keyword "pulse oximetry" has the strongest strength in the middle of the chart connected with the rest of the keywords as "oxygen saturation" and "patient monitoring".

    “The keyword “pulse oximetry” has the strongest strength in the middle of the chart connected with the rest of the keywords as “oxygen saturation”, and “patient monitoring”.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    A portable EEL reflectance spectrophotometer to measure natural pigmentation (not darkened by sun-tanning) was employed in 1 study (2.70%).

    “Besides, a portable EEL reflectance spectrophotometer to measure natural pigmentation (not darkened by sun-tanning) was employed in 1 study ( 2.70%) [46].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [46] Bothma, 1996, Accuracy of pulse oximetry in pigmented patients, S. Afr. Med. J.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The keyword "COVID-19" appears in 2020 near to the keywords "hypoxemia", "oxygen-therapy", "intensive-care", "diagnostic accuracy", and "dark-skin population".

    “The keyword “COVID-19” appears in 2020 near to the keywords, “hypoxemia”, “oxygen-therapy”, “intensive-care”, “diagnostic accuracy”, and “dark-skin population” among others.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    To date, the effects of skin pigment on pulse oximeter performance have been studied for only a relatively small number of pulse oximeter models, and most of them have been calibrated using light-skinned individuals.

    “It is also worthy to remark that, to date, the effects of skin pigment on pulse oximeter performance have been studied for only a relatively small number of pulse oximeter models, and most of them have been calibrated using light-skinned individuals.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    A prevalence of occult hypoxemia in dark-skinned subjects has been recently confirmed in three studies, showing that dark-skinned patients may have over three times the risk of experiencing occult hypoxemia during hospitalization compared to light-skinned patients.

    “A prevalence of occult hypoxemia in dark-skinned subjects has been recently confirmed in three studies, showing that dark-skinned patients may have over three times the risk of experiencing occult hypoxemia during hospitalization compared to light-skinned patients [53,54,55].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [53] Henry, 2022, Disparities in Hypoxemia Detection by Pulse Oximetry Across Self-Identified Racial Groups and Associations with Clinical Outcomes, Crit. Care Med. source

      Not checked in the free run.

    • cites [54] Wong, 2021, Analysis of Discrepancies between Pulse Oximetry and Arterial Oxygen Saturation Measurements by Race and Ethnicity and Association with Organ Dysfunction and Mortality, JAMA Netw. Open source

      Not checked in the free run.

    • cites [55] Valbuena, 2021, Racial Bias in Pulse Oximetry Measurement Among Patients About to Undergo Extracorporeal Membrane Oxygenation in 2019–2020: A Retrospective Cohort Study, Chest

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Two authors independently performed the bibliographic search.

    “Two authors (AMC and MFG) independently performed the bibliographic search, while the search algorithm was reviewed and discussed with the rest of the authors (PM, KL or DL).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    M.W. Sjoding et al. found overestimations in dark-skinned patients with an increased risk of occult hypoxemia.

    “Besides, they found overestimations in dark-skinned patients with an increased risk of occult hypoxemia [50].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [50] Sjoding, 2020, Racial Bias in Pulse Oximetry Measurement, N. Engl. J. Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The five authors performed the quality and eligibility assessment of relevant references.

    “The five authors performed the quality and eligibility assessment of relevant references.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Bickler et al. tested the effect of skin pigmentation under hypoxia in 11 dark-skinned male subjects and 10 light-skinned males breathing a nitrogen-carbon monoxide mixture; the three pulse oximeters used showed overestimation in dark-skinned individuals that increases linearly as SpO2 levels decrease.

    “The effect of skin pigmentation in pulse oximeter readings under hypoxia conditions was tested in 11 dark-skinned male subjects and 10 light-skinned males, who were made to breathe an air mixture (nitrogen-carbon monoxide). The three pulse oximeters used showed overestimation in dark-skinned individuals that increases linearly as SpO2 levels decreases [23].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [23] Bickler, 2005, Effects of skin pigmentation on pulse oximeter accuracy at low saturation, Anesthesiology source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Risk of bias was assessed using the QUADAS-2 protocol based on four domains: patient selection, index test, reference standard, and flow and timing.

    “Although there is no a standard risk of bias tool for methods-comparison studies, we follow the QUADAS-2 protocol based on four domains: patient selection, index test, reference standard, and flow and timing of patients [90].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [90] Whiting, 2011, QUADAS-2: A revised tool for the quality assessment of diagnostic accuracy studies, Ann. Intern. Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    A review of 13 models of pulse oximeters suggested that a high percentage of carboxyhemoglobin or methaemoglobin are related to failures in saturation readings and can hide hypoxemia.

    “A review of 13 models of pulse oximeters suggested that a high percentage of carboxyhemoglobin or methaemoglobin are related to failures in saturation readings and can hide hypoxemia [86].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [86] Ralston, 1991, Potential errors in pulse oximetry. I. Pulse oximeter evaluation, Anaesthesia source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Fallow et al. found a better resolution using a green-light wavelength at rest and a green or blue-light wavelength in motion across all skin types.

    “Indeed, Fallow et al. found a better resolution using a green-light wavelength at rest and a green or blue-light wavelength in motion across all skin types [80].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [80] Fallow, 2013, Influence of skin type and wavelength on light wave reflectance, J. Clin. Monit. Comput. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Titles, abstracts, and author keywords were first independently analyzed by two authors, and full texts were examined by five authors to check inclusion criteria.

    “Titles, abstracts, and author’s keywords were first independently analyzed to get enough information about the eligibility of two authors (AMC and MFG, or PM). Second, we carefully examined the full text to check whether the references satisfy the inclusion criteria by the five authors.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Feiner et al. conclude that pulse oximeter inaccuracy is reasonably small at SpO2>80% because of dark skin pigmentation, but a bias of up to 8% was detected at lower saturation conditions in dark-skinned individuals.

    “Feiner et al. conclude that pulse oximeter inaccuracy is reasonably small at SpO2>80% because of dark skin pigmentation [24]. However, a bias of up to 8% was detected at lower saturation conditions in dark-skinned individuals.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [24] Feiner, 2007, Dark skin decreases the accuracy of pulse oximeters at low oxygen saturation: The effects of oximeter probe type and gender, Anesth. Analg. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The review applied the PRISMA statement to conduct the systematic review.

    “The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was applied to pre-identified the selected studies indexed in PubMed, Web of Science (WOS), and Scopus databases.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Lee et al. found that estimation of arterial oxygen pressure, SaO2, varied significantly (p < 0.05) in multi-ethnic individuals (22 Chinese, 6 Malay and 5 Indian), and the difference between SpO2 and SaO2 appeared to increase with darker skin pigmentation, with overestimations more pronounced under conditions of hypoxia and jaundice.

    “Lee et al. also observed this bias in an older study, finding that the estimation of arterial oxygen pressure, SaO2, varied significantly (p < 0.05) in multi-ethnic individuals (22 Chinese, 6 Malay and 5 Indian). The results suggested that the difference between SpO2 and SaO2 appeared to increase with darker skin pigmentation, with overestimations more pronounced under conditions of hypoxia and ja”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [85] Lee, 1993, Factors influencing pulse oximetry as compared to functional arterial saturation in multi-ethnic Singapore, Singap. Med. J.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    M.W. Sjoding et al. conducted a study in two large cohorts at the University of Michigan Hospital comparing SpO2 and arterial blood gas measurements in over 10,000 people with 14-20% dark-skinned patients in both cohorts.

    “They conducted this study in two large cohorts at the University of Michigan Hospital comparing measurements of SpO2 and arterial blood gas of a sample of over 10,000 people with 14–20% of dark-skinned patients in both cohorts.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [50] Sjoding, 2020, Racial Bias in Pulse Oximetry Measurement, N. Engl. J. Med. source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Because dark skin contains more melanin, several studies assert that pulse oximetry may not be reliable in dark-skinned patients.

    “Because dark skin contains more melanin, several studies assert that pulse oximetry may not be reliable in dark-skinned patients [21,23,24,50,51,53,69,73,75,76,78,80,87,88,89,93].”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Dark skin contains more melanin.

  • May combine two claims.

    Premisecitation

    Studies on healthy adults with different skin pigmentation showed that red and green wavelengths could estimate oxygen saturation with good agreement and lower error ratio compared to the traditional pulse oximeter.

    “Studies on healthy adults with different skin pigmentation showed that red and green wavelengths could estimate oxygen saturation with good agreement and lower error ratio compared to the traditional pulse oximeter [30,80,102].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [30] Al-Naji, A., Khalid, G.A., Mahdi, J.F., and Chahl, J. (2021). Non-Contact SpO2 Prediction System Based on a Digital Camera. Appl. Sci., 11. source

      Not checked in the free run.

    • cites [80] Fallow, 2013, Influence of skin type and wavelength on light wave reflectance, J. Clin. Monit. Comput. source

      Not checked in the free run.

    • cites [102] Maeda, 2011, The advantages of wearable green reflected photoplethysmography, J. Med. Syst. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Baek et al. performed desaturation experiments at 60% to 100% on healthy adults with different skin pigmentation; conventional sensors showed a large error in dark-skinned subjects, while the crosstalk-free sensor did not present SpO2 measurement errors according to skin color.

    “Accuracy improvements were found with a crosstalk-free sensor designed by Baek et al. who performed desaturation experiments at 60% to 100% on healthy adults with different skin pigmentation [75]. The conventional sensors showed a large error in dark-skinned subjects, while the sensor which prevented optical crosstalk did not present SpO2 measurement errors according to skin color.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [75] Baek, 2018, The Effect of Optical Crosstalk on Accuracy of Reflectance-Type Pulse Oximeter for Mobile Healthcare, J. Healthc. Eng. source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Darker skin pigmentation affects the reliability of pulse oximeters, and when used by a patient for home monitoring, confirmation of a medical-grade oximeter is required.

    “They advise that darker skin pigmentation affects the reliability of these pulse oximeters, and when used by a patient for home monitoring, confirmation of a medical-grade oximeter is required [71].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [71] Harskamp, 2021, Performance of popular pulse oximeters compared with simultaneous arterial oxygen saturation or clinical-grade pulse oximetry: A cross-sectional validation study in intensive care patients, BMJ Open Respir. Res.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Patients with hidden hypoxemia have higher rates of in-hospital mortality and organ dysfunction.

    “This finding is of particular importance since patients with hidden hypoxemia have higher rates of in-hospital mortality and organ dysfunction [55].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [55] Valbuena, 2021, Racial Bias in Pulse Oximetry Measurement Among Patients About to Undergo Extracorporeal Membrane Oxygenation in 2019–2020: A Retrospective Cohort Study, Chest

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Some older studies did not identify a considerable bias related to skin pigmentation, suggesting that dark skin pigmentation does not affect the quality of the signal.

    “Conversely, some older studies did not identify a considerable bias related to skin pigmentation [44,45,46,56] suggesting that dark skin pigmentation does not affect the quality of the signal [47].”
    Quote in the paperNot a substantial claim0 of 5 sources checked
    • cites [44] Wang, 1985, Noninvasive oximetry in pigmented patients, Ann. Acad. Med.

      Not checked in the free run.

    • cites [45] Gabrielczyk, 1988, Pulse oximetry and postoperative hypothermia, Anaesthesia source

      Not checked in the free run.

    • cites [46] Bothma, 1996, Accuracy of pulse oximetry in pigmented patients, S. Afr. Med. J.

      Not checked in the free run.

    • cites [56] Avant, 1997, G; Lowe N.; Torres Jr., A. Comparison of accuracy and signal consistency of two reusable pulse oximeter probes in critically ill children, Respir. Care

      Not checked in the free run.

    • cites [47] Adler, 1998, Effect of skin pigmentation on pulse oximetry accuracy in the emergency department, Acad. Emerg. Med. Off. J. Soc. Acad. Emerg. Med. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A study about applying a pulse oximeter device in titration of fractional inspired O2 concentration in ventilator-dependent patients revealed that a SpO2 reading of 92% was reliable when titrating supplemental O2 in light-skinned patients receiving mechanical ventilation, but in dark-skinned patients the same SpO2 value was commonly related to significant hypoxemia, and higher SpO2 measurements of

    “A study about applying a pulse oximeter device in the titration of fractional inspired O2 concentration in ventilator-dependent patients revealed that a SpO2 reading of 92% was reliable when titrating supplemental O2 in light-skinned patients receiving mechanical ventilation. However, in dark-skinned patients, the same SpO2 value was commonly related to significant hypoxemia, and a higher SpO2”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [88] Jubran, 1990, Reliability of pulse oximetry in titrating supplemental oxygen therapy in ventilator-dependent patients, Chest source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Green-wavelength pulse oximeters display the greatest modulation depth with pulsatile blood absorption, i.e., a greater absorbance for both deoxyhemoglobin and oxyhemoglobin than infrared light.

    “Green-wavelength pulse oximeters display the greatest modulation depth with pulsatile blood absorption, i.e., a greater absorbance for both deoxyhemoglobin and oxyhemoglobin than infrared light [40].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [40] Tamura, 2014, Wearable photoplethysmographic sensors—past and present, Electronics source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    The main reason for the upsurge of publications in 2021 may be attributed to the increase of pulse oximetry for triage in patients because of the COVID-19 pandemic and recent concern about accuracy across all skin types.

    “The main reason for this surge may be attributed to the increase of this technique for triage in patients because of the current COVID-19 pandemic [12,13,14,15,16,17], and also because of the recent concern about the accuracy of these devices across all skin types [20,57,58,59,60,61].”
    Quote in the paperNot a substantial claim0 of 10 sources checked
    • cites [12] Scherrenberg, M., Wilhelm, M., Hansen, D., Völler, H., Cornelissen, V., Frederix, I., Kemps, H., and Dendale, P. (2020). The future is now: A call for action for cardiac telerehabilitation in the COVID-19 pandemic from the secondary prevention and rehabilitation section of the European Association of Preventive Cardiology. Eur. J. Prev. Cardiol., 1–21. source

      Not checked in the free run.

    • cites [13] Channa, A., Popescu, N., Skibinska, J., and Burget, R. (2021). The Rise of Wearable Devices during the COVID-19 Pandemic: A Systematic Review. Sensors, 21. source

      Not checked in the free run.

    • cites [14] Philip, 2020, Working accuracy of pulse oximetry in COVID-19 patients stepping down from intensive care: A clinical evaluation, BMJ Open Respir. Res.

      Not checked in the free run.

    • cites [15] Michard, 2021, COVID-19: Pulse oximeters in the spotlight, J. Clin. Monit. Comput. source

      Not checked in the free run.

    • cites [16] England NHS (2020, March 26). Specialty Guides for Patient Management during the Coronavirus Pandemic. Guidance for the Role and Use of Non-Invasive Respiratory Support in Adult Patients with COVID-19 (Confirmed or Suspected) 6 April 2020, Version 2. Available online: https://amhp.org.uk/app/uploads/2020/03/Guidance-Respiratory-Support.pdf.

      Not checked in the free run.

    • cites [17] Wiles, 2021, The effect of patient ethnicity on the accuracy of peripheral pulse oximetry in patients with COVID-19 pneumonitis: A single-centre, retrospective analysis, Anaesthesia source

      Not checked in the free run.

    • cites [20] World Health Organization (2021). COVID-19 Clinical Management: Living Guidance, 25 January 2021, World Health Organization. Technical Documents.

      Not checked in the free run.

    • cites [57] Warren, R., and Wyden, C.B. (2021). 2021.01.25 Letter to FDA re Bias in Pulse Oximetery Measurements, Technical Report; U.S. Food and Drug Administration.

      Not checked in the free run.

    • cites [58] NHS Race & Health Observatory (2021). Pulse Oximetry and Racial Bias: Recommendations for National Healthcare, Regulatory and Research Bodies, National Health Service England. Technical Report March.

      Not checked in the free run.

    • cites [59] Hunasikatti, 2021, Racial bias in accuracy of pulse oximetry and its impact on assessments of hypopnea and T90 in clinical studies, J. Clin. Sleep Med. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    More recent studies have revealed that dark skin pigmentation influences the accuracy and performance of pulse oximeter devices, resulting in overestimations, with increased incidence in the risk for occult hypoxemia (SO2<88% despite normal SpO2>92%).

    “More recent studies have also revealed that dark skin pigmentation influences the accuracy and performance of pulse oximeters devices, resulting in overestimations [17,49,50,51,52,53] with increased incidence in the risk for occult hypoxemia (SO2<88% despite normal SpO2>92%) [54,55].”
    Quote in the paperSubstantial claim0 of 8 sources checked
    • cites [17] Wiles, 2021, The effect of patient ethnicity on the accuracy of peripheral pulse oximetry in patients with COVID-19 pneumonitis: A single-centre, retrospective analysis, Anaesthesia source

      Not checked in the free run.

    • cites [49] Bent, 2020, Investigating sources of inaccuracy in wearable optical heart rate sensors, NPJ Digit. Med. source

      Not checked in the free run.

    • cites [50] Sjoding, 2020, Racial Bias in Pulse Oximetry Measurement, N. Engl. J. Med. source

      Not checked in the free run.

    • cites [51] Vesoulis, 2021, Racial discrepancy in pulse oximeter accuracy in preterm infants, J. Perinatol. source

      Not checked in the free run.

    • cites [52] Okunlola, 2022, Pulse Oximeter Performance, Racial Inequity, and the Work Ahead, Respir. Care source

      Not checked in the free run.

    • cites [53] Henry, 2022, Disparities in Hypoxemia Detection by Pulse Oximetry Across Self-Identified Racial Groups and Associations with Clinical Outcomes, Crit. Care Med. source

      Not checked in the free run.

    • cites [54] Wong, 2021, Analysis of Discrepancies between Pulse Oximetry and Arterial Oxygen Saturation Measurements by Race and Ethnicity and Association with Organ Dysfunction and Mortality, JAMA Netw. Open source

      Not checked in the free run.

    • cites [55] Valbuena, 2021, Racial Bias in Pulse Oximetry Measurement Among Patients About to Undergo Extracorporeal Membrane Oxygenation in 2019–2020: A Retrospective Cohort Study, Chest

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The older findings of no considerable bias may be misleading because of a small sample size of the dark-skinned population or a weak correlation with skin pigmentation by using uncertain descriptors of ancestry to classify the population.

    “However, these findings may be misleading because of a small sample size of the dark-skinned population or a weak correlation with skin pigmentation by using uncertain descriptors of ancestry to classify the population.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Conventional red and infrared pulse oximeters are reliable at rest and in normoxic or hyperoxic conditions, but have presented worsening accuracy in hypoxic conditions.

    “Conventional red and infrared pulse oximeters are reliable at rest and in normoxic or hyperoxic conditions, but have presented worsening accuracy in hypoxic conditions [23].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [23] Bickler, 2005, Effects of skin pigmentation on pulse oximeter accuracy at low saturation, Anesthesiology source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A recent comprehensive review comparing SpO2 measurements with arterial blood gas analysis SaO2 in different patients and conditions reported accurate but imprecise measurements across all levels of skin pigmentation.

    “A recent comprehensive review of different studies comparing SpO2 measurements with arterial blood gas analysis SaO2 in different patients and conditions has reported accurate but imprecise measurements across all levels of skin pigmentation [61].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [61] Shi, C., Goodall, M., Dumville, J., Hill, J.E., Norman, G., Hamer, O., Clegg, A., Watkins, C.L., Georgiou, G., and Alexander Hodkinson, A. (2022). Article The effects of skin pigmentation on the accuracy of pulse oximetry in measuring oxygen saturation: A systematic review and meta-analysis The effects of skin pigmentation on the accuracy of pulse and meta-analysis. PLoS Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The current World Health Organization COVID-19 management guideline recommends that symptomatic people with COVID-19 use a home pulse oximeter for self SpO2 monitoring "as part of a package of care".

    “Therefore, the current World Health Organization COVID-19 management guideline recommends that symptomatic people with COVID-19 to use a home pulse oximeter for self SpO2 monitoring “as part of a package of care” [20].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [20] World Health Organization (2021). COVID-19 Clinical Management: Living Guidance, 25 January 2021, World Health Organization. Technical Documents.

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Several health organizations and healthcare professionals have raised growing concerns about the clinical accuracy of pulse oximetry in dark-skinned patients, particularly in detecting occult hypoxemia.

    “Due to this increasing evidence, several health organizations and healthcare professionals have raised growing concerns about the clinical accuracy of pulse oximetry in dark-skinned patients [20,57,58,59,60,61], particularly in detecting occult hypoxemia [54,55].”
    Quote in the paperSubstantial claim0 of 8 sources checked
    • cites [20] World Health Organization (2021). COVID-19 Clinical Management: Living Guidance, 25 January 2021, World Health Organization. Technical Documents.

      Not checked in the free run.

    • cites [57] Warren, R., and Wyden, C.B. (2021). 2021.01.25 Letter to FDA re Bias in Pulse Oximetery Measurements, Technical Report; U.S. Food and Drug Administration.

      Not checked in the free run.

    • cites [58] NHS Race & Health Observatory (2021). Pulse Oximetry and Racial Bias: Recommendations for National Healthcare, Regulatory and Research Bodies, National Health Service England. Technical Report March.

      Not checked in the free run.

    • cites [59] Hunasikatti, 2021, Racial bias in accuracy of pulse oximetry and its impact on assessments of hypopnea and T90 in clinical studies, J. Clin. Sleep Med. source

      Not checked in the free run.

    • cites [60] Holder, 2022, The Big Consequences of Small Discrepancies: Why Racial Differences in Pulse Oximetry Errors Matter, Crit. Care Med. source

      Not checked in the free run.

    • cites [61] Shi, C., Goodall, M., Dumville, J., Hill, J.E., Norman, G., Hamer, O., Clegg, A., Watkins, C.L., Georgiou, G., and Alexander Hodkinson, A. (2022). Article The effects of skin pigmentation on the accuracy of pulse oximetry in measuring oxygen saturation: A systematic review and meta-analysis The effects of skin pigmentation on the accuracy of pulse and meta-analysis. PLoS Med. source

      Not checked in the free run.

    • cites [54] Wong, 2021, Analysis of Discrepancies between Pulse Oximetry and Arterial Oxygen Saturation Measurements by Race and Ethnicity and Association with Organ Dysfunction and Mortality, JAMA Netw. Open source

      Not checked in the free run.

    • cites [55] Valbuena, 2021, Racial Bias in Pulse Oximetry Measurement Among Patients About to Undergo Extracorporeal Membrane Oxygenation in 2019–2020: A Retrospective Cohort Study, Chest

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The skin pigmentation effect on pulse oximetry accuracy has long been studied, reporting some contradictory conclusions.

    “The skin pigmentation effect on pulse oximetry accuracy has long been studied reporting some contradictory conclusions.”
    • Also stated in: § 1. Introduction · plain
      “Skin pigmentation impact on the accuracy of SpO2 monitoring has long been studied [24,41,42,43,44,45,46,47,48,49,50,51].”
    Quote in the paperSubstantial claim0 of 10 sources checked
    • cites [24] Feiner, 2007, Dark skin decreases the accuracy of pulse oximeters at low oxygen saturation: The effects of oximeter probe type and gender, Anesth. Analg. source

      Not checked in the free run.

    • cites [41] Saunders, 1976, Ear oximetry: Accuracy and tracticability in the assessment of arterial oxygenation, Am. Rev. Respir. Dis.

      Not checked in the free run.

    • cites [42] Emery, 1987, Skin pigmentation as an influence on the accuracy of pulse oximetry, J. Perinatol. Off. J. Calif. Perinat. Assoc.

      Not checked in the free run.

    • cites [43] Cecil, 1988, A clinical evaluation of the accuracy of the Nellcor N-100 and Ohmeda 3700 pulse oximeters, J. Clin. Monit. source

      Not checked in the free run.

    • cites [44] Wang, 1985, Noninvasive oximetry in pigmented patients, Ann. Acad. Med.

      Not checked in the free run.

    • cites [45] Gabrielczyk, 1988, Pulse oximetry and postoperative hypothermia, Anaesthesia source

      Not checked in the free run.

    • cites [46] Bothma, 1996, Accuracy of pulse oximetry in pigmented patients, S. Afr. Med. J.

      Not checked in the free run.

    • cites [47] Adler, 1998, Effect of skin pigmentation on pulse oximetry accuracy in the emergency department, Acad. Emerg. Med. Off. J. Soc. Acad. Emerg. Med. source

      Not checked in the free run.

    • cites [48] Foglia, 2017, The Effect of Skin Pigmentation on the Accuracy of Pulse Oximetry in Infants with Hypoxemia, J. Pediatr. source

      Not checked in the free run.

    • cites [49] Bent, 2020, Investigating sources of inaccuracy in wearable optical heart rate sensors, NPJ Digit. Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    During exercise, the main potential errors are due to motion artifact, which complicates the use of the pulse oximeter and the accurate interpretation of the data.

    “Although during exercise, the main potential errors are due to motion artifact, which complicates the use of the pulse oximeter and the accurate interpretation of the data [29,30,31]”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [29] Tobin, 2002, A characterization of motion affecting pulse oximetry in 350 patients, Anesth. Analg.

      Not checked in the free run.

    • cites [30] Al-Naji, A., Khalid, G.A., Mahdi, J.F., and Chahl, J. (2021). Non-Contact SpO2 Prediction System Based on a Digital Camera. Appl. Sci., 11. source

      Not checked in the free run.

    • cites [31] 2014, Improved motion robustness of remote-PPG by using the blood volume pulse signature, Physiol. Meas. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The FSP scale is commonly used to describe skin pigmentation according to the skin tanning response to UVR.

    “The FSP scale is commonly used to describe skin pigmentation according to the skin tanning response to UVR [105,106,107].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [105] Fitzpatrick, 1963, The epidermal melanin unit system, Dermatol. Wochenschr.

      Not checked in the free run.

    • cites [106] Fitzpatrick, 1988, The validity and practicality of sun-reactive skin types I through VI, Arch. Dermatol. source

      Not checked in the free run.

    • cites [107] Moreiras, 2021, Visible light and human skin pigmentation: The importance of skin phototype, Exp. Dermatol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Fallow et al. found that phototype-V (dark brown) skin type has a significant signal-to-noise ratio than all other skin types.

    “Fallow et al. classified 23 healthy subjects (11 males and 12 females, 20–59 years old) finding that phototype-V (dark brown) skin type has a significant signal-to-noise ratio than all other skin types [80].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [80] Fallow, 2013, Influence of skin type and wavelength on light wave reflectance, J. Clin. Monit. Comput. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Pulse oximetry performance in the dark-skinned population may lead to overestimations with increased incidence of occult hypoxemia and risk of negative health effects from diseases like COVID-19.

    “To sum up, we conclude that pulse oximetry performance in the dark-skinned population may lead to overestimations with increased incidence of occult hypoxemia and risk of negative health effects from diseases like COVID-19 [51,53,55].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [51] Vesoulis, 2021, Racial discrepancy in pulse oximeter accuracy in preterm infants, J. Perinatol. source

      Not checked in the free run.

    • cites [53] Henry, 2022, Disparities in Hypoxemia Detection by Pulse Oximetry Across Self-Identified Racial Groups and Associations with Clinical Outcomes, Crit. Care Med. source

      Not checked in the free run.

    • cites [55] Valbuena, 2021, Racial Bias in Pulse Oximetry Measurement Among Patients About to Undergo Extracorporeal Membrane Oxygenation in 2019–2020: A Retrospective Cohort Study, Chest

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The recent camera-based SpO2 study did not stratify results according to level of skin pigmentation, which can introduce considerable errors.

    “However, they did not stratify their results according to the level of skin pigmentation, which can introduce considerable errors.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    A study of 26,603 patients across four self-identified racial groups found that pulse oximetry accuracy for detection of occult hypoxemia is not consistent across these groups, with SpO2 measurements on average overestimating arterial blood gas-derived oxygen saturation by 1.57%.

    “also found that the pulse oximetry accuracy for the detection of occult hypoxemia is not consistent across these self-identified ethnic groups with SpO2 measurements on average overestimating arterial blood gas-derived oxygen saturation by 1.57% [53].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [53] Henry, 2022, Disparities in Hypoxemia Detection by Pulse Oximetry Across Self-Identified Racial Groups and Associations with Clinical Outcomes, Crit. Care Med. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    These pulse oximeters have probably been calibrated on a population sample with light-skin pigmentation, which miss relevant interaction effects of confounding variables and skin pigmentation.

    “Besides, these pulse oximeters have probably been calibrated on a population sample with light-skin pigmentation, which miss relevant interaction effects of confounding variables and skin pigmentation [23,33,109].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [23] Bickler, 2005, Effects of skin pigmentation on pulse oximeter accuracy at low saturation, Anesthesiology source

      Not checked in the free run.

    • cites [33] Colvonen, 2021, Response to: Investigating sources of inaccuracy in wearable optical heart rate sensors, NPJ Digit. Med. source

      Not checked in the free run.

    • cites [109] Xiao, 2017, Characterising the variations in ethnic skin colours: A new calibrated data base for human skin, Skin Res. Technol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A study in 298 patients classified by the Munsell color system concluded that skin pigmentation does not affect the bias or precision of pulse oximetry.

    “In contrast, a study conducted in 298 patients classified according to the Munsell color system [108] as light group (51%), intermediate group (37%), and dark group (12%) conclude that skin pigmentation does not affect the bias or precision of pulse oximetry.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [108] Munsell, A.H. (1915). Atlas of the Munsell Color System, Wadsworth, Howland & Co., Inc., Printers. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Two old studies (1997 with 50 children, 15 dark-skinned; 1996 with 100 dark-skinned patients) did not find any difference in accuracy between dark and light-skinned subjects.

    “Two more old studies, one in 1997 with a sample of 50 children, 15 of whom were dark-skinned [56] and another in 1996 with 100 dark-skinned patients [46], did not find any difference in accuracy between dark and light-skinned subjects.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [56] Avant, 1997, G; Lowe N.; Torres Jr., A. Comparison of accuracy and signal consistency of two reusable pulse oximeter probes in critically ill children, Respir. Care

      Not checked in the free run.

    • cites [46] Bothma, 1996, Accuracy of pulse oximetry in pigmented patients, S. Afr. Med. J.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Baek et al. found large errors in the dark-skinned subjects with the pulse oximeter that did not prevent crosstalk.

    “They found large errors in the dark-skinned subjects with the pulse oximeter that did not prevent crosstalk.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [75] Baek, 2018, The Effect of Optical Crosstalk on Accuracy of Reflectance-Type Pulse Oximeter for Mobile Healthcare, J. Healthc. Eng. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    One study asserted that there is no significant difference in systematic bias based on skin pigment for pulse oximetry, but this study was not statistically significant since it had a small sample size and a stringent inclusion criterion.

    “Although one study asserted that there is no significant difference in systematic bias based on skin pigment for pulse oximetry [48], this study was not statistically significant since it had a small sample size and a stringent inclusion criterion that was not typical for premature infants.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [48] Foglia, 2017, The Effect of Skin Pigmentation on the Accuracy of Pulse Oximetry in Infants with Hypoxemia, J. Pediatr. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Feiner et al. advised that a significant bias in dark-skinned patients with saturation below 80% should be considered.

    “They advised that a significant bias in dark-skinned patients with saturation below 80% should be considered.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Feiner, 2007, Dark skin decreases the accuracy of pulse oximeters at low oxygen saturation: The effects of oximeter probe type and gender, Anesth. Analg. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Although some old studies did not find any bias related to dark skin pigmentation, the latter studies have shown that pulse oximeters devices have some limitations with dark-skinned subjects, especially at low saturation or hypoxemia conditions.

    “Although some old studies did not find any bias related to dark skin pigmentation, the latter studies have shown that pulse oximeters devices have some limitations with dark-skinned subjects, especially at low saturation or hypoxemia conditions.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Two studies found a small but consistent skin pigmentation disparity in SpO2 measurements with values that may be falsely high in dark-skinned preterm infants.

    “The other two studies found a small but consistent skin pigmentation disparity in SpO2 measurements with values that may be falsely high in dark-skinned preterm infants [51,74].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [51] Vesoulis, 2021, Racial discrepancy in pulse oximeter accuracy in preterm infants, J. Perinatol. source

      Not checked in the free run.

    • cites [74] Poets, 2019, Noninvasive Monitoring and Assessment of Oxygenation in Infants, Clin. Perinatol. source

      Not checked in the free run.

59 of 59

  • The paper relies on this without support.

    Dark skin contains more melanin.

    “Because dark skin contains more melanin, several studies assert that pulse oximetry may not be reliable in dark-skinned patients [21,23,24,50,51,53,69,73,75,76,78,80,87,88,89,93].”

  • The paper relies on this without support.

    Occult hypoxemia is associated with increased mortality risk.

    “Since occult hypoxemia is associated with increased mortality risk, there is a need to determine such errors exactly.”
2 of 2

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • There have been systematic reviews on PPG skin pigmentation bias, but these have been limited to either consumer device PR or pulse oximeter SpO2.

    “There have been systematic reviews on PPG skin pigmentation bias, but these have been limited to either consumer device PR [35] or pulse oximeter SpO2 [36-38].”

    From Impact of skin pigmentation on pulse oximetry blood oxygenation and wearable pulse rate accuracy: systematic review and meta-analysis (2024) · cites this paper as [37]

  • The use of secondary measurement methods, including HRV derived from heart rate values, produces assessments that can be inaccurate for stress and recovery evaluation.

    “The use of secondary measurement methods, including heart rate variability (HRV) derived from heart rate values, produces assessments that can be inaccurate for stress and recovery evaluation [32].”

    From Photoplethysmography in Diverse Skin Tones: Evaluating Bias in Smartwatch Health Monitoring (2025) · cites this paper as [32]

    The Introduction discusses pulse oximetry during exercise stress tests and respiratory rehabilitation, while the Final Remarks describe inaccuracies in oxygen-saturation readings, particularly for dark-skinned individuals. Neither section addresses HRV derived from heart-rate values or the accuracy of stress and recovery assessments. Searches for those terms and for secondary measurement methods found no passage addressing the claim. (LLM, conf=0.75)

    Experimental — accuracy not yet measured

  • Skin pigmentation affects the accuracy of PO.

    “A recent flurry in publications identifies that skin pigmentation affects the accuracy of PO.11,134–140”

    From Effect of skin color on optical properties and the implications for medical optical technologies: a review (2024) · cites this paper as [134]

  • Black and ethnic minority groups had poorest outcomes from COVID-19 infection and this was compounded by the overestimation of oxygen saturation.

    “Black and ethnic minority groups had poorest outcomes from COVID-19 infection and this was compounded by the overestimation of oxygen saturation.11,134”

    From Effect of skin color on optical properties and the implications for medical optical technologies: a review (2024) · cites this paper as [134]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Incorrect percentage of dark-skinned participants in Foglia study

    Minor

    Fourteen out of 36 participants is 38.89%, not 40.00%.

    Reported 40 · recomputed 38.888889

  • Wiles study gender counts exceed its sample size

    Minor

    The listed male and female counts total 294, whereas the table gives a sample size of 194.

    Reported 194 · recomputed 294

  • Ebmeier study gender counts fall short of its sample size

    Minor

    The listed male and female counts total 294, whereas the table gives a sample size of 394. The table does not indicate whether gender was unavailable for the remaining participants.

    Reported 394 · recomputed 294

  • Incorrect percentage of dark-skinned participants in Ebmeier study

    Minor

    The table lists 65 dark-skinned participants out of 394, which is 16.50%, not 16.09%.

    Reported 16.09 · recomputed 16.497462

  • Adler study has two different sample sizes

    Minor

    Table 3 gives 284 participants for Adler et al. [47], while the discussion describes the same study as having 298 patients.

  • Ebmeier study has two different sample sizes

    Minor

    Table 3 lists 394 participants for Ebmeier et al. [76], but the discussion says its skin-phototype classification covered 404 ICU patients.

  • Fallow study age ranges disagree

    Minor

    Table 3 reports ages 19-43 for Fallow et al. [80], while the discussion describes the same 23-person study as ages 20-59.

  • Fallow skin-classification method disagrees between table and discussion

    Minor

    Table 3 calls Fallow et al.'s method a subjective dark-or-light scale, whereas the discussion says the study used the Fitzpatrick Skin Pigmentation scale.

  • Low-risk study outcome categories total twelve, not eleven

    Minor

    The paragraph says there were 11 low-risk studies, but assigns 8 to inaccuracies, 3 to no demonstrable loss of accuracy, and 1 to a further-studies conclusion-a total of 12.

    Reported 11 · recomputed 12

  • Wiles ethnicity counts do not total the stated patient count

    Minor

    The three reported ethnicity counts total 188, not the stated 194 patients; the text does not account for the other six.

    Reported 194 · recomputed 188

10 of 10

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. Avant, 1997, G; Lowe N.; Torres Jr., A. Comparison of accuracy and signal consistency of two reusable pulse oximeter probes in critically ill children, Respir. Care, 42, 698
  2. Hameedullah, 2002, Henna paste and pulse oximetry: Effect of different methods of application, J. Anaesthesiol. Clin. Pharmacol., 18, 193

Cited by

Sorted by citations

Related

Authors
Cabanas, A. M., Fuentes-Guajardo, M., Latorre, K., León, D., & Martín-Escudero, P.
Affiliations
  • University of Tarapacá (CL)
  • Departamento de Tecnología Médica, Universidad de Tarapacá, Arica 1010069, Chile
  • Universidad Complutense de Madrid (ES)
Corresponding author
Cabanas, Ana M.
ORCID
Venue
Sensors
Publisher
MDPI AG
Published
2022-04-29
Volume
22
Issue
9
Pages
3402
ISSN
1424-8220 (ISSN-L)
DOI
10.3390/s22093402
PMC
PMC9102088
OpenAlex
W4225276305
Semantic Scholar
cb2ae9e7d44263c7ee8c31d947e317d0aae398f7
Cited by
124
References
107
Citations by year
2026: 15 · 2025: 29 · 2024: 43 · 2023: 34 · 2022: 3
FWCI
2.43
Type
journal article
Language
en
Open access
Licence
Locations
  • Sensors (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
UTA-Mayor Project (7721-20)
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Non-Invasive Vital Sign Monitoring
  • Health Sciences › Medicine › Surgery › Hemodynamic Monitoring and Therapy
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Optical Imaging and Spectroscopy Techniques
Keywords
pulse oximetry, skin pigmentation, oxygen saturation measurement, measurement error, dark skin, low oxygen saturation, COVID-19 triage, bibliometric analysis, scientometrics
MeSH terms
COVID-19, Humans, Oximetry, Oxygen, Retrospective Studies, Skin Pigmentation, Bibliometrics, Pandemics

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review