Mixing studies in lupus anticoagulant testing are required at least in some type of samples
Open accessAbstract
Background According to the ISTH guidelines for lupus anticoagulant (LAC) testing, the second step in the three-step procedure (screening, mixing, and confirmation) is the mixing test, which improves the discrimination between the presence of an inhibitor and coagulation factor deficiencies such as those occurring in patients receiving vitamin K antagonists (VKAs).Objectives From a retrospective analysis of dilute Russell viper venom (dRVVT) results, we evaluated the impact of the mixing test result on the interpretation of LAC positivity.Methods We interpreted the dRVVT clotting times with and without taking into account the results of the mixing test in a patient population with prolonged screening test (n = 267) with special attention to the patients receiving VKAs.Results and conclusions The number of samples classified as 'LAC positive' differed substantially depending on the method of interpretation; 170 and 235 of 267 samples were classified as LAC positive with the three- and two-step procedure, respectively. Discrepancy between the two-step (without mixing step) and the three-step procedure was due to not including a mixing test and was more pronounced in the VKA patient population. Screen/confirm ratios carried out on a 1:1 mix of patient and normal pooled plasma (NPP) gave a lower incidence of 59 of 267. We advise continuing to perform mixing test to avoid false-positives. In patients with discrepant results between the two- and three-step dRVVT interpretation, mainly observed in VKA-treated patients, we advise retesting of the patients preferable beyond the period of anticoagulant therapy and additional testing for anti-beta2GPI and/or anti-cardiolipin antibodies.
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Written from the paper’s full text.
TL;DR
In a retrospective dRVVT analysis of 267 patients with prolonged screening tests, LAC positivity differed substantially by interpretation method: 170/267 by the three-step procedure versus 235/267 by the two-step procedure without mixing. The authors advise continuing to perform mixing tests to avoid false positives, especially in VKA-treated patients, and recommend re-testing after anticoagulant cessation when results are discrepant.
Key findings
- Among 267 patients with prolonged dRVVT screening, 170/267 were classified LAC positive by the three-step procedure (including mixing) versus 235/267 by the two-step procedure (Screen/Confirm ratio without mixing); 65/267 showed discrepant results.
- Discrepancy was more pronounced in VKA patients: 113 LAC positive by two-step versus 64 by three-step in VKA patients, compared with 96 versus 86 in non-VKA patients.
- Negative mixing tests occurred in 69/140 VKA patients versus 11/101 non-VKA patients; 64/140 VKA patients had a positive mixing test and could be classified LAC positive.
- Confirm CT was significantly more prolonged in VKA patients (median 1.47, 95% CI 1.41–1.50) than non-VKA patients (median 1.23, 95% CI 1.21–1.26; P<0.0001), while Screen/Confirm ratios did not differ significantly (median 1.38 vs 1.31; P=0.1891). The third interpretation using Screen/Confirm on a 1:1 mix gave a lower number of LAC-positive samples: 44/241 in the Results (the Summary reports 59/267).
Methods
- Retrospective review of dRVVT results (LA Screen and LA Confirm, Life Diagnostics; STAR analyser, Diagnostica Stago) from a consecutive Ghent University Hospital cohort of 3707 samples over one year; 267 patients with prolonged dRVVT screening test were analyzed.
- For all samples, Screen CT, Confirm CT, Screen CT on a 1:1 patient plasma:normal pooled plasma mix, and Confirm mix were performed; results were interpreted as LAC-1 (three-step: Screen CT, Screen mix, Screen/Confirm ratio), LAC-2 (two-step: Screen/Confirm ratio without mixing), or LAC-3 (Screen/Confirm mix).
- Results were expressed as normalized ratios with in-house cut-offs calculated at the 99th percentile; mixing tests were interpreted using the 99th percentile of healthy donors mixed with normal pooled plasma. VKA patients had INR values ranging from 1.4–6.4.
Limitations
- Stated: there is no gold standard for LAC testing and no clear identification of which process reflects “true LAC”; the clinical significance of weak or “incompletely defined” LAC, especially in VKA patients, remains uncertain and needs more thorough evaluation, including studies before and after starting VKA.
- Stated: this was a retrospective analysis; medical records were available for only a subset re-analyzed (n=124), and discrepancy data for that subset were not shown.
- Evident: the study is single-center, uses one dRVVT reagent system and in-house cut-offs, and lacks independent clinical outcome adjudication, so generalizability to other reagents, laboratories, and patient populations is uncertain.
Model-written summary. Check it against the paper before relying on it.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
4 of 18 cited sources checked · 3 supported · 0 flagged · accuracy not yet measured
- Premisecitation
The mixing test is mainly to discriminate between the presence of an inhibitor and coagulation factor deficiencies such as those occurring in patients on VKA.
“The mixing test is mainly to discriminate between the presence of an inhibitor and coagulation factor deficiencies such as those occurring in patients on conventional oral anticoagulants/vitamin K antagonists (VKA).”
Quote in the paperSubstantial claim1 of 2 sources checked- cites [1] 1. Pengo V, Tripodi A, Reber G, Rand JH, Ortel TL, Galli M, De Groot PG. Update of the guidelines for lupus anticoagulant detection. Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the International Society on Thrombosis and Haemostasis. J Thromb Haemost. 2009;7:1737-40. source
The Mixing test section (page unavailable) specifies normal plasma with approximately 100% activity of all clotting factors and notes that inhibitors can prolong a mixing test. The section on LA detection in patients taking VKA (page unavailable) discusses prolonged clotting times and possible mixing with normal plasma. Our copy does not explicitly say that the mixing test is mainly used to distinguish inhibitors from factor deficiencies, or identify VKA-related factor deficiencies as that comparison. (LLM, conf=0.79)
Experimental — accuracy not yet measured - cites [2] 2. Clinical and Laboratory Standards Institute. Laboratory testing for the lupus anticoagulant; Approved guideline, Wayne PA USA, CLSI Document H60-A. 2014. This article is protected by copyright. All rights reserved.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Findingown data
In total, 65/267 samples showed a discrepant result between the three and two step procedure.
“In total, 65/267 samples showed a discrepant result between the three and two step procedure.”
Quote in the paperSubstantial claim - Findingown data
The number of samples classified as LAC positive differed substantially depending on the method of interpretation.
“The number of samples classified as LAC positive differed substantially depending on the method of interpretation (Figure 1).”
- Also stated in: § Results and conclusions · plain
“The number of samples classified as”
Quote in the paperSubstantial claim - Also stated in: § Results and conclusions · plain
- Findingown data
170/267 samples were classified as LAC positive with the three-step procedure.
“170/267 and 235/267 samples were classified as LAC positive with the three step and the two step procedure, respectively.”
Quote in the paperSubstantial claim - Findingown data
Screen/Confirm ratios carried out on a 1:1 mix of patient and NPP gave a lower incidence of 59/267.
“Screen/Confirm ratios carried out on a 1:1 mix of patient and NPP gave a lower incidence of 59/267.”
Quote in the paperSubstantial claim
- Findingown data
235/267 samples were classified as LAC positive with the two-step procedure.
“170/267 and 235/267 samples were classified as LAC positive with the three step and the two step procedure, respectively.”
Quote in the paperSubstantial claim - Findingown data
The third method (LAC-3) resulted in a lower number of LAC positive samples (44/241).
“The third method of interpretation applying the Screen and Confirm on a 1:1 mix for the samples with prolonged neat Confirm CT (LAC-3) resulted in a lower number of LAC positive samples (44/241).”
Quote in the paperSubstantial claim - Findingown data
There is no argument to assume that the VKA patients in this study have a weaker LAC compared to non-VKA patients (median Screen/Confirm ratio 1.38 vs 1.31, not significantly different P=0.1891).
“we have no argument to assume that the VKA patients in our study have a weaker LAC compared to non-VKA patients (median Screen/Confirm ratio 1.38 (95% CI for the median = 1.32-1.40) versus 1.31 (95% CI for the median = 1.28-1.39), not significantly different (P=0.1891) for VKA and non-VKA patients, respectively).”
Quote in the paperSubstantial claim - Findingown data
The discrepancy was more pronounced in the VKA-patient population (113 LAC positive in two step vs 64 in three step) compared to non-VKA (96 vs 86).
“Discrepancy between the two step and three step procedure was due to omission of a mixing test and was more pronounced in the VKA-patient population (113 LAC positive in two step procedure vs 64 in three step procedure) compared to the non-VKA patient population (96 LAC positive in two step procedure vs 86 in three step procedure).”
Quote in the paperSubstantial claim - Findingnone given
Omitting the mixing test captures more LAC positives in the non-VKA patients.
“Moreover, omitting the mixing test captures more”
Quote in the paperSubstantial claim - Findingown data
Comparison of positive Screen/Confirm ratio of patients with negative Screen mix, positive Screen mix, and positive Screen/Confirm ratio on PP:NPP mix showed that the Screen/Confirm ratio raised significantly according to these three groups.
“Comparison of the positive Screen/Confirm ratio of patients with a negative Screen mix test (n=49 VKA patients, n=10 non-VKA patients), a positive Screen mix test (n=64 VKA patients, n=86 non-VKA patients) and a positive Screen/Confirm ratio on a PP:NPP mix (n=16 VKA patients, n=28 non-VKA patients) showed that the Screen/Confirm ratio raised significantly according to these three groups (Figure 2”
Quote in the paperSubstantial claim - Premisecitation
Otherwise many of the abnormal results interpreted without the mixing test resulted in false positive LAC.
“Otherwise many of the abnormal results interpreted without the mixing test resulted in false positive LAC (3).”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [3] 3. Devreese KM. No more mixing tests required for integrated assay systems in the laboratory diagnosis of lupus anticoagulants? J Thromb Haemost. 2010;8:1120-2.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Interpretationown data
The value of the Screen/Confirm ratio taken as a measure of strength for LAC suggests that LAC are indeed diluted out by mixing, regarding the decreasing number of positive samples from group A towards group C.
“The value of the Screen/Confirm ratio taken as a measure of strength for LAC, suggests that LAC are indeed diluted out by mixing regarding the decreasing number of positive samples from group A towards group C.”
Quote in the paperSubstantial claim- The authors state this as an assumption: The Screen/Confirm ratio can be taken as a measure of LAC strength.
- Interpretationreasoning
The large number of negative mixing tests in VKA patients (69/140) compared to non-VKA (11/101) is probably due to factor deficiency corrected by mixing the plasma.
“The large number of negative mixing tests in the VKA patients (69/140) compared to the negative mixing tests in the non-VKA group (11/101) is probably due to the factor deficiency corrected by mixing the plasma.”
Quote in the paperSubstantial claim - Interpretationown data
In this selection of patients, the expression of true LAC positivity in the dRVVT test system depends on the inclusion of a mixing test.
“In conclusion, in this selection of patients the expression of true LAC positivity in the dRVVT test system depends on the inclusion of a mixing test.”
Quote in the paperSubstantial claim- Rests on an assumption: The three-step procedure including the mixing test identifies true LAC positivity more accurately than the two-step procedure without mixing.
- Premisecitation
A reduced sensitivity is likely to be expected for weak LAC when these are diluted in the mixture of PP and NPP except in the case of the cofactor effect.
“A reduced sensitivity is likely to be expected for weak LAC, when these are diluted in the mixture of PP and NPP except in the case of the cofactor effect (4, 13).”
Quote in the paperSubstantial claim0 of 2 sources checked - Interpretationown data
Omitting the mixing test as suggested by Pennings et al is likely to increase the false positive rate significantly, as shown by the results presented here.
“Omitting the mixing test as suggested by Pennings et al (6) is likely to increase the false positive rate significantly as shown by the results presented here.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [6] 6. Pennings MT, De Groot PG, Meijers JC, Huisman A, Derksen RH, Urbanus RT. Optimisation of lupus anticoagulant tests: should test samples always be mixed with normal plasma? Thromb Haemost. 2014;112:736-42. source
- Rests on an assumption: The three-step procedure including the mixing test identifies true LAC positivity more accurately than the two-step procedure without mixing.
- Interpretationreasoning
Since there was no reason to suspect the presence of weaker LAC in this VKA group, these patients would have been misclassified as LAC positive without the mixing test.
“Since there was no reason to suspect the presence of weaker LAC in this VKA group, these patients would have been misclassified as”
Quote in the paperSubstantial claim- Rests on an assumption: The three-step procedure including the mixing test identifies true LAC positivity more accurately than the two-step procedure without mixing.
- Interpretationown data
Discrepancy between the two step and three step procedure was due to omission of a mixing test.
“Discrepancy between the two step and three step procedure was due to omission of a mixing test and was more pronounced in the VKA-patient population (113 LAC positive in two step procedure vs 64 in three step procedure) compared to the non-VKA patient population (96 LAC positive in two step procedure vs 86 in three step procedure).”
Quote in the paperSubstantial claim- Rests on an assumption: The three-step procedure including the mixing test identifies true LAC positivity more accurately than the two-step procedure without mixing.
- Interpretationown data
The phospholipid rich dRVVT CT may be affected by factors other than those involved in the PT, as suggested by the relatively large numbers of patients with prolonged Confirm CT even in the non-VKA group.
“The phospholipid rich dRVVT CT may be affected by factors other than those involved in the PT as suggested by the relatively large numbers of patients with prolonged Confirm CT even in the non-VKA group.”
Quote in the paperSubstantial claim - Interpretationown data
Factor deficiency induced by VKA strongly influences the results of the mixing tests (correction of CT as currently defined) overruling the effect of the inhibitor.
“This indicates that factor deficiency induced by VKA strongly influences the results of the mixing tests (= correction of CT as currently defined) overruling the effect of the inhibitor.”
Quote in the paperSubstantial claim
- Classified as probably not a substantial claim. 5
- May combine two claims. 4
Classified as probably not a substantial claim.
PremisecitationAccording to ISTH/SSC and CLSI guidelines, LAC identification should include three steps: screening, mixing, and confirmation.
“According to ISTH/SSC (1) and CLSI (2) guidelines LAC identification should include three steps: screening for prolongation in a phospholipid-sensitive test, mixing with normal plasma to identify failure to correct and confirmation through result shortening in a phospholipid-rich test, (though in slightly different priority with CLSI).”
Quote in the paperSubstantial claim1 of 2 sources checked- cites [1] 1. Pengo V, Tripodi A, Reber G, Rand JH, Ortel TL, Galli M, De Groot PG. Update of the guidelines for lupus anticoagulant detection. Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the International Society on Thrombosis and Haemostasis. J Thromb Haemost. 2009;7:1737-40. source
- cites [2] 2. Clinical and Laboratory Standards Institute. Laboratory testing for the lupus anticoagulant; Approved guideline, Wayne PA USA, CLSI Document H60-A. 2014. This article is protected by copyright. All rights reserved.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Classified as probably not a substantial claim.
Study design and conductcitationResults were interpreted according to in-house calculated cut-off values calculated with the 99th percentile.
“Results were expressed as normalized ratios and interpreted according to in-house calculated cut-off values calculated with the 99th percentile (1).”
Quote in the paperSubstantial claim1 of 1 sources checked- cites [1] 1. Pengo V, Tripodi A, Reber G, Rand JH, Ortel TL, Galli M, De Groot PG. Update of the guidelines for lupus anticoagulant detection. Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the International Society on Thrombosis and Haemostasis. J Thromb Haemost. 2009;7:1737-40. source
May combine two claims.
PremisecitationTesting patients during VKA or other anticoagulant therapy for LAC remains a contentious issue and has been discouraged by official guidelines because of interpretational problems affecting the mixing test.
“Testing patients during VKA or other anticoagulant therapy for LAC remains a contentious issue and has been discouraged by official guidelines (1, 2) because of interpretational problems affecting the mixing test (8-10).”
Quote in the paperSubstantial claim1 of 5 sources checked- cites [1] 1. Pengo V, Tripodi A, Reber G, Rand JH, Ortel TL, Galli M, De Groot PG. Update of the guidelines for lupus anticoagulant detection. Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the International Society on Thrombosis and Haemostasis. J Thromb Haemost. 2009;7:1737-40. source
- cites [2] 2. Clinical and Laboratory Standards Institute. Laboratory testing for the lupus anticoagulant; Approved guideline, Wayne PA USA, CLSI Document H60-A. 2014. This article is protected by copyright. All rights reserved.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [8] 8. Aboud M, Morel-Kopp MC, Ward C, Coyle L. False-negative or false-positive: laboratory diagnosis of lupus anticoagulant at the time of commencement of anticoagulant. J Thromb Haemost 2010;8:2070-3.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [9] 9. Aboud M, Morel-Kopp MC, Ward C, Coyle L. False negative or false positive: laboratory diagnosis of lupus anticoagulant at the time of commencement of anticoagulant: reply to a rebuttal. J Thromb Haemost. 2011;9:1436-7.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [10] 10. Tripodi A, Moia M, Pengo V. False-negative or false-positive: laboratory diagnosis of lupus anticoagulant at the time of commencement of anticoagulant: a rebuttal. J Thromb Haemost. 2011;9:1435-6. source
Probably not a substantial claim: may not pass S3 (load-bearing).
Findingown dataDiscrepancies between the interpretation methods for LAC were equal in the re-analyzed patient group (n=124) compared to the overall patient group.
“Discrepancies between the interpretation methods for LAC were equal in this patient group compared to the overall patient group (data not shown).”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown dataIn the VKA patients 64/140 do have a positive mixing test and can be classified as LAC positive.
“In the VKA patients 64/140 do have a positive mixing test and can be classified as”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
PremisecitationPreviously it has been recommended that mixing tests should be applied at least when the clotting time of the dRVVT confirmatory test is outside the reference range.
“Previously it has been recommended that mixing tests should be applied at least when the clotting time of the dRVVT confirmatory test is outside the reference range (3).”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [3] 3. Devreese KM. No more mixing tests required for integrated assay systems in the laboratory diagnosis of lupus anticoagulants? J Thromb Haemost. 2010;8:1120-2.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
PremisecitationAlthough most commercial dRVVT reagents behave almost similar in LAC testing, differences have been observed.
“Although most of the commercial dRVVT reagents behave almost similar in LAC testing, it is important to note that differences have been observed (11, 12).”
Quote in the paperNot a substantial claim0 of 2 sources checked- cites [11] 11. Chantarangkul V, Biguzzi E, Asti D, Palmucci C, Tripodi A. Laboratory diagnostic outcome applying detection criteria recommended by the Scientific and Standardization Committee of the ISTH on Lupus Anticoagulant. Thrombosis and haemostasis. 2013;110:46-52.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- cites [12] 12. McGlasson DL, Fritsma GA. Comparison of six dilute russell viper venom time lupus anticoagulant screen/confirm assay kits. Semin Thromb Hemost. 2013;39:315-9. source
May combine two claims.
PremisecitationTesting for LAC during VKA or other anticoagulant therapy is still performed in labs because many LAC/APS patients are on anticoagulants, patients may suffer re-thrombosis if taken off their treatment, and it is reasonably reliable if carried out correctly.
“However it is still performed in labs because many LAC/APS patients are on anticoagulants, patients may suffer re-thrombosis if taken off their treatment and also because it is reasonably reliable if carried out correctly (9).”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [9] 9. Aboud M, Morel-Kopp MC, Ward C, Coyle L. False negative or false positive: laboratory diagnosis of lupus anticoagulant at the time of commencement of anticoagulant: reply to a rebuttal. J Thromb Haemost. 2011;9:1436-7.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
The paper relies on this without support.
The three-step procedure including the mixing test identifies true LAC positivity more accurately than the two-step procedure without mixing.
“In conclusion, in this selection of patients the expression of true LAC positivity in the dRVVT test system depends on the inclusion of a mixing test.”
“However, there is no gold standard for LAC testing and therefore no clear identification of which process actually reflects 'true LAC'.”
The authors state this as an assumption.
The Screen/Confirm ratio can be taken as a measure of LAC strength.
“The value of the Screen/Confirm ratio taken as a measure of strength for LAC, suggests that LAC are indeed diluted out by mixing regarding the decreasing number of positive samples from group A towards group C.”
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?
A mixing test in the confirmatory step increases diagnostic efficacy when there are coexisting causes of clotting time prolongation or a strong LA.
“This increases the diagnostic efficacy, 14,35 when there are coexisting reasons for clotting time prolongation (factor deficiency or VKA) or a strong LA sufficiently potent to overcome the excess of PL added in the confirmatory step.52”
From Guidance from the Scientific and Standardization Committee for lupus anticoagulant/antiphospholipid antibodies of the International Society on Thrombosis and Haemostasis (2020) · cites this paper as [35]
The Introduction and Results and discussion (pages not supplied) support mixing tests to distinguish lupus anticoagulant from factor deficiency, particularly in VKA-treated patients, and to reduce false positives when confirmatory clotting time is prolonged. The paper does not establish the claimed benefit specifically for a strong lupus anticoagulant that overcomes the excess phospholipid in the confirmatory step. (LLM, conf=0.84)
Experimental — accuracy not yet measuredOmitting the mixing step may produce false-positive and false-negative LA results.
“More recent studies illustrate that omitting the mixing step may give false-positive and false-negative results.35,58,60”
From Guidance from the Scientific and Standardization Committee for lupus anticoagulant/antiphospholipid antibodies of the International Society on Thrombosis and Haemostasis (2020) · cites this paper as [35]
The Results and conclusions (page not available in our copy) advise retaining the mixing test to avoid false-positive LA results. The paper does not establish that omitting the mixing step produces false negatives; its Results and discussion instead note that mixing can dilute weak LA. Thus only the false-positive part is supported. (LLM, conf=0.88)
Experimental — accuracy not yet measuredVitamin K antagonists may cause false-positive or false-negative LA results.
“Vitamin K antagonists (VKAs) may cause false-positive or false-negative results.34,35”
From Guidance from the Scientific and Standardization Committee for lupus anticoagulant/antiphospholipid antibodies of the International Society on Thrombosis and Haemostasis (2020) · cites this paper as [35]
The Results and discussion report that omitting the mixing test would misclassify many VKA-treated patients as LA-positive, supporting the false-positive risk. The paper also discusses weak LA being diluted out by mixing and recommends retesting after anticoagulant therapy, but it does not establish that VKAs themselves cause false-negative results. (LLM, conf=0.83)
Experimental — accuracy not yet measuredInformation from the confirmatory test can aid interpretation even when the mixing step is negative.
“However, information on the confirmatory test, even if the mixing step is negative, can help in the interpretation.34,35,58”
Mixing tests add information about screening and confirmatory testing, especially in samples from anticoagulated patients.
“On the other hand, mixing tests add information on the results of screening and confirmatory testing, especially in anticoagulated patient samples.35”
Coagulation factor deficiency strongly influences the results of mixing tests.
“Our results also suggest that coagulation factor deficiency strongly influences the results of mixing tests [10].”
From Performance characteristics of 5 numerical indexes in mixing test interpretation under coexistence of lupus anticoagulant and coagulation factor deficiency (2023) · cites this paper as [10]
In situations where alternative or co-existing coagulation abnormalities are present, mixing tests can improve specificity of LA testing.
“However, in situations where alternative or co‐existing coagulation abnormalities are present, mixing tests can improve specificity of LA testing.34, 35, 36, 37”
Interpretation of LA tests for patients on VKA remains controversial, and VKA use is associated with false negative and false positive LA results.
“Interpretation of LA tests for patients on VKA remains controversial, and VKA use is associated with false negative and false positive LA results.25,26”
From Lupus anticoagulant test persistence over time and its associations with future thrombotic events (2022) · cites this paper as [25]
Cites
Update of the guidelines for lupus anticoagulant detection
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Self-citationLaboratory investigation of lupus anticoagulants: mixing studies are sometimes required
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Self-citationComparison of six dilute Russell viper venom time lupus anticoagulant screen/confirm assay kits
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<i>In</i> ECAT <i>veritas?</i>
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Self-citationAntiphospholipid antibodies in patients with COVID‐19: A relevant observation?
Devreese, K. M. J., Linskens, E. A., Benoît, D., & Peperstraete, H. (2020) · Journal of Thrombosis and Haemostasis · doi:10.1111/jth.14994 · Cited by 190 · see citing works
“Ventilation duration (days), median (range) 18 (4-50)”
BackgroundSelf-citationDevreese, K. M. J., Bertolaccini, M. L., Branch, D. W., de Laat, B., Erkan, D., Favaloro, E. J., Pengo, V., Ortel, T. L., Wahl, D., & Cohen, H. (2025) · Journal of Thrombosis and Haemostasis · doi:10.1016/j.jtha.2024.10.022 · Cited by 92 · see citing works
Self-citationThe Lupus Anticoagulant Paradox
Molhoek, J. E., de Groot, P. G., & Urbanus, R. T. (2017) · Seminars in Thrombosis and Hemostasis · doi:10.1055/s-0037-1606190 · Cited by 50 · see citing works
De Kesel, P. M. M., & Devreese, K. M. J. (2020) · Research and Practice in Thrombosis and Haemostasis · doi:10.1002/rth2.12264 · Cited by 47 · see citing works
Self-citationMoore, G. W., Jones, P. O., Platton, S., Hussain, N., White, D., Thomas, W., Rigano, J., Pouplard, C., Gray, E., & Devreese, K. M. J. (2021) · Journal of Thrombosis and Haemostasis · doi:10.1111/jth.15438 · Cited by 47 · see citing works
Self-citationMoore, G. W., Culhane, A. P., Daw, C. R., Noronha, C. P., & Kumano, O. (2016) · Thrombosis Research · doi:10.1016/j.thromres.2016.01.019 · Cited by 42 · see citing works
“Mixing tests with both screen and confirm assays were performed to increase specificity [5, 6], particularly in situationswhere confirmatory test ratios were themselves elevated [6, 7, 13, 14].”
BackgroundMethodResultInfluentialCox‐Morton, S., MacDonald, S. G., & Thomas, W. (2019) · British Journal of Haematology · doi:10.1111/bjh.16091 · Cited by 40 · see citing works
De Kesel, P. M., & Devreese, K. M. J. (2020) · Journal of Thrombosis and Haemostasis · doi:10.1111/jth.14894 · Cited by 40 · see citing works
Self-citationAPS - Diagnostics and challenges for the future
Pengo, V., Bison, E., Zoppellaro, G., Jose, S. P., Denas, G., Hoxha, A., Ruffatti, A., & Banzato, A. (2016) · Autoimmunity Reviews · doi:10.1016/j.autrev.2016.07.028 · Cited by 37 · see citing works
Laboratory Diagnostics of Antiphospholipid Syndrome
Bison, E., Denas, G., Jose, S., Zoppellaro, G., Banzato, A., & Pengo, V. (2017) · Seminars in Thrombosis and Hemostasis · doi:10.1055/s-0037-1601331 · Cited by 36 · see citing works
The challenges of lupus anticoagulants
Chighizola, C. B., Raschi, E., Banzato, A., Borghi, M. O., Pengo, V., & Meroni, P. L. (2016) · Expert Review of Hematology · doi:10.1586/17474086.2016.1140034 · Cited by 36 · see citing works
Current Controversies in Lupus Anticoagulant Detection
Moore, G. (2016) · Antibodies · doi:10.3390/antib5040022 · Cited by 36 · see citing works
“Evidence for absence of a co-existing abnormality largely comes from the coagulation screen employing a LA-insensitive routine APTT, if normal, but also from the confirmatory test whose partner screening test was elevated, in that a normal confirmatory test is additional evidence that interfering factors specific to t…”
BackgroundInfluentialTesting for Lupus Anticoagulants
Moore, G. W. (2022) · Seminars in Thrombosis and Hemostasis · doi:10.1055/s-0042-1744363 · Cited by 30 · see citing works
Laboratory testing for antiphospholipid syndrome
Pengo, V., Banzato, A., Bison, E., Denas, G., Zoppellaro, G., Bracco, A., Jose, S. P., Hoxha, A., & Ruffatti, A. (2016) · International Journal of Laboratory Hematology · doi:10.1111/ijlh.12507 · Cited by 29 · see citing works
“the mixing step may determine false-positive [3] and false-negative results [4, 5].”
BackgroundInterference of DOACs in different DRVVT assays for diagnosis of lupus anticoagulants
Flieder, T., Weiser, M., Eller, T., Dittrich, M. T., von Bargen, K., Alban, S., Kühn, J., Knabbe, C., & Birschmann, I. (2018) · Thrombosis Research · doi:10.1016/j.thromres.2018.03.009 · Cited by 29 · see citing works
Kumano, O., & Moore, G. W. (2018) · Research and Practice in Thrombosis and Haemostasis · doi:10.1002/rth2.12069 · Cited by 26 · see citing works
Moore, G. W., Culhane, A. P., Maloney, J. C., Archer, R. A., Breen, K. A., & Hunt, B. J. (2015) · Blood Coagulation & Fibrinolysis · doi:10.1097/mbc.0000000000000486 · Cited by 25 · see citing works
Lupus Anticoagulant Testing: Diluted Russell Viper Venom Time (dRVVT)
Pengo, V., Bison, E., Banzato, A., Zoppellaro, G., Jose, S. P., & Denas, G. (2017) · Methods in Molecular Biology · doi:10.1007/978-1-4939-7196-1_14 · Cited by 21 · see citing works
Moore, G. W., Maloney, J. C., de Jager, N., Dunsmore, C. L., Gorman, D. K., Polgrean, R. F., & Bertolaccini, M. L. (2017) · Research and Practice in Thrombosis and Haemostasis · doi:10.1002/rth2.12006 · Cited by 20 · see citing works
Sennesael, A., Exner, T., Châtelain, B., et al. (2017) · Thrombosis Research · doi:10.1016/j.thromres.2017.06.034 · Cited by 18 · see citing works
Testa, S., Meijer, P., Lasne, D., & Mullier, F. (2022) · International Journal of Laboratory Hematology · doi:10.1111/ijlh.13936 · Cited by 14 · see citing works
“The implementation of normalized ratios and mixing studies with NPPs reduces laboratory variability and increase lupus anticoagulant diagnosis specificity.(58) However, the problematic around NPPs is”
BackgroundMoore, G. W., Peyrafitte, M., Dunois-Lardé, C., & Amiral, J. (2017) · Lupus · doi:10.1177/0961203317711773 · Cited by 14 · see citing works
Amiral, J., Peyrafitte, M., Dunois-Lardé, C., Vissac, A. M., & Seghatchian, J. (2017) · Transfusion and Apheresis Science · doi:10.1016/j.transci.2017.07.014 · Cited by 15 · see citing works
Evaluation of an automated algorithm for interpretation of lupus anticoagulant testing
Florin, L., Desloovere, M., & Devreese, K. M. J. (2019) · International Journal of Laboratory Hematology · doi:10.1111/ijlh.13001 · Cited by 12 · see citing works
Self-citationVariability among commercial batches of normal pooled plasma in lupus anticoagulant testing
Cabo, J., Morimont, L., Baudar, J., Guldenpfennig, M., Jacqmin, H., Soleimani, R., Lecompte, T., Douxfils, J., & Mullier, F. (2022) · International Journal of Laboratory Hematology · doi:10.1111/ijlh.13977 · Cited by 12 · see citing works
“Other authors, in contrast argue that mixing studies are a powerful tool to differentiate factor deficiencies from coagulation inhibitors and increase the specificity of LA testing.(12,31,32) Mixing studies also allow the detection of paradoxical LA cofactor effect.”
BackgroundA review of laboratory considerations in thrombophilia testing
Ong, J., & Bennett, A. (2022) · Pathology · doi:10.1016/j.pathol.2022.09.001 · Cited by 11 · see citing works
Chandrashekar, V. (2015) · Blood Coagulation & Fibrinolysis · doi:10.1097/mbc.0000000000000463 · Cited by 11 · see citing works
Wysokinska, E. M., & Ortel, T. L. (2019) · Elsevier eBooks · doi:10.1016/b978-0-323-46202-0.00020-0 · Cited by 11 · see citing works
Laboratory Diagnosis of the Lupus Anticoagulant
Smith, L. J. (2017) · American Society for Clinical Laboratory Science · doi:10.29074/ascls.30.1.7 · Cited by 11 · see citing works
Coagulation Testing in Real-World Setting: Insights From a Comprehensive Survey
Bang, H. I., Lee, J. Y., Kim, H., Shin, S., Nam, M., Kim, I., Kim, J., Yoon, J., Shin, M., Hwang, S. M., et al. (2024) · Clinical and Applied Thrombosis/Hemostasis · doi:10.1177/10760296241228239 · Cited by 8 · see citing works
“9,22,32 According to our survey results, 81.5% (22 of 27) of the institutions proceed with testing in patients undergoing anticoagulant therapy regardless of the treatment.”
BackgroundInfluentialMoore, G. W. (2017) · Thrombosis Research · doi:10.1016/j.thromres.2017.09.017 · Cited by 8 · see citing works
“However, mixing tests increase diagnostic specificity and confidence, and are useful when other coagulation disturbances are known or suspected to be present, or where a LA is sufficiently potent achieve a degree of resistance against the overwhelming effect of high PL concentration confirmatory reagents [2,5,8].”
BackgroundRoselli, D., Bonifacio, M. A., Barbuti, G., Rossiello, M. R., Ranieri, P., & Mariggiò, M. A. (2023) · Diagnostics · doi:10.3390/diagnostics13152507 · Cited by 7 · see citing works
“Similar to Devreese [24], LA results were graded as follows, i.e., 0 (both assays negative), 1 (one positive assay), 2 (two positive assays) and 3 (two positive assays with prolonged aPTT and/or PT).”
ResultLaboratory Diagnosis of Antiphospholipid Syndrome
An, G., Lim, H., & Han, J. (2017) · Clinical & Experimental Thrombosis and Hemostasis · doi:10.14345/ceth.17002 · Cited by 7 · see citing works
“17002 geous on the detection of weaker LA, but still raising concern on the performance of mixing tests.(22,23) All three guidelines concur that it is not ideal to test for LA while the patients are being treated with anticoagulant therapy.”
BackgroundDepreter, B., & Devreese, K. M. J. (2016) · Clinical Chemistry and Laboratory Medicine (CCLM) · doi:10.1515/cclm-2015-0978 · Cited by 34 · see citing works
Self-citationAntiphospholipid Syndrome and Kidney Involvement
Simone, E. D., Sciascia, S., Fenoglio, R., Oddone, V., Barreca, A., & Roccatello, D. (2023) · Kidney & Blood Pressure Research · doi:10.1159/000529229 · Cited by 11 · see citing works
“Subsequently, con fi rmatory test is performed to exclude the possibility of a coagulation factor de fi ciency [39, 40] and to con fi rm that adding phospholipids to the serum of the patients induces normalization of the clotting time [38].”
MethodLupus anticoagulant test persistence over time and its associations with future thrombotic events
Colling, M. E., Ay, C., Kraemmer, D., Koder, S., Quehenberger, P., Pabinger, I., Posch, F., & Gebhart, J. (2022) · Blood Advances · doi:10.1182/bloodadvances.2021006011 · Cited by 5 · see citing works
“This corresponded to 10-year prospective ATE, VTE, and overall thrombosis incidences of 14% (95%CI: 9-21), 20% (13-28), and 34% (26-43), respectively, and a 10-year mortality of 14% (9-22) (supplemental Figure 2).”
BackgroundAnalytical dilemmas in lupus anticoagulant detection
Moore, G. W. (2023) · Exploration of Immunology · doi:10.37349/ei.2023.00104 · Cited by 5 · see citing works
Viewpoint: Lupus anticoagulant detection and interpretation in antiphospholipid syndrome
Efthymiou, M., Bertolaccini, M. L., & Cohen, H. (2024) · Rheumatology · doi:10.1093/rheumatology/kead623 · Cited by 5 · see citing works
Lupus anticoagulant laboratory diagnosis by applying the 2020 ISTH-SSC guidelines
Talon, L., Fourneyron, V., Senectaire, S., Tardieu, M., Tillier, M., Trapani, A., Trayaud, A., Vaissade, A., Sapin, A.-F. S., Lebreton, A., et al. (2023) · Thrombosis Research · doi:10.1016/j.thromres.2023.02.009 · Cited by 5 · see citing works
Lupus Anticoagulant Testing: Taipan Snake Venom Time with Ecarin Time as Confirmatory Test
Moore, G. W. (2023) · Methods in Molecular Biology · doi:10.1007/978-1-0716-3175-1_16 · Cited by 5 · see citing works
Lupus Anticoagulant Testing: Dilute Prothrombin Time (dPT)
Moore, G. W. (2023) · Methods in molecular biology · doi:10.1007/978-1-0716-3175-1_17 · Cited by 5 · see citing works
Matsuda, M., Hoshiyama, Y., Ogawa, K., Emmi, M., Terai, S., & Moriyama, M. (2023) · Research and Practice in Thrombosis and Haemostasis · doi:10.1016/j.rpth.2023.100065 · Cited by 4 · see citing works
“Our results also suggest that coagulation factor deficiency strongly influences the results of mixing tests [10].”
BackgroundResultAntiphospholipid Antibodies in Patients With Lupus Anticoagulant Prozone Effect
Murphy, C., Jin, J., & Zehnder, J. L. (2019) · American Journal of Clinical Pathology · doi:10.1093/ajcp/aqz151 · Cited by 4 · see citing works
Ieko, M., Ohmura, K., Naito, S., Yoshida, M., Sasaki, H., Sato, T., Sugawara, N., Takahashi, N., & Ichinose, A. (2023) · Exploration of Immunology · doi:10.37349/ei.2023.00103 · Cited by 4 · see citing works
Sciascia, S., Radin, M., & Schreiber, K. I. (2024) · Elsevier eBooks · doi:10.1016/b978-0-443-23947-2.00045-x · Cited by 3 · see citing works
Lupus Anticoagulant Testing in Challenging Situations: Navigating Complexities
Devreese, K. M. J. (2026) · International Journal of Laboratory Hematology · doi:10.1111/ijlh.14490 · Cited by 2 · see citing works
Self-citationMixing studies for lupus anticoagulant: does it matter how we mix?
Biljak, V. R., Tomas, M., & Lapić, I. (2024) · Blood Coagulation & Fibrinolysis · doi:10.1097/mbc.0000000000001288 · Cited by 2 · see citing works
Testing lupus anticoagulants in a real-life scenario - a retrospective cohort study
Ratzinger, F., Panić‐Janković, T., Haslacher, H., Perkmann, T., Schmetterer, K. G., Belik, S., Maenner, G., Pabinger, I., & Quehenberger, P. (2017) · Biochemia Medica · doi:10.11613/bm.2017.030705 · Cited by 2 · see citing works
“However, when mixing tests are omitted, false negative results related to a very strong LAC, but false positives especially in patients with VKA have also been reported (21,22).”
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Sex-specific cut-off for dilute Russell’s viper venom time lupus anticoagulant test may be of value
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Novelli, C., Gatti, A., Ierna, F., Riccardi, E., & Cuppari, I. (2026) · International Journal of Laboratory Hematology · doi:10.1111/ijlh.70153
- Authors
- Devreese, K. M. J., & de Laat, B.
- Affiliations
- Ghent University Hospital (BE)
- Corresponding author
- Devreese, K.M.J.
- ORCID
- Devreese, K.M.J.
- Venue
- Journal of Thrombosis and Haemostasis
- Publisher
- Elsevier BV
- Published
- 2015-08
- Volume
- 13
- Issue
- 8
- Pages
- 1475-1478
- ISSN
- 1538-7836 (ISSN-L)
- OpenAlex
- W1550350302
- Semantic Scholar
- 875789a7b88b165a6d520d91a3ffe703ffcfcf13
- Cited by
- 63
- References
- 14
- Citations by year
- 2026: 1 · 2025: 2 · 2024: 8 · 2023: 9 · 2022: 6 · 2021: 1 · 2020: 4 · 2019: 6 · 2018: 5 · 2017: 13 · 2016: 6 · 2015: 2
- FWCI
- 6.34
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Licence
- Locations
- Journal of Thrombosis and Haemostasis (publishedVersion)
- PubMed (publishedVersion)
- Research Publications (Maastricht University) (publishedVersion, other-oa)
- Ghent University Academic Bibliography (Ghent University) (submittedVersion)
- Research Publications (Maastricht University) (submittedVersion, other-oa)
- Topics
- Health Sciences › Medicine › Rheumatology › Systemic Lupus Erythematosus Research
- Health Sciences › Medicine › Hematology › Blood Coagulation and Thrombosis Mechanisms
- Health Sciences › Medicine › Surgery › Heparin-Induced Thrombocytopenia and Thrombosis
- Keywords
- lupus anticoagulant, mixing test, dilute Russell viper venom time, vitamin K antagonists, coagulation factor deficiency, false positives, anti-beta2-glycoprotein I antibodies, anticardiolipin antibodies, anticoagulation
- MeSH terms
- Anticoagulants, Blood Coagulation, Humans, Predictive Value of Tests, Prothrombin Time, Retrospective Studies, Vitamin K, Reproducibility of Results, Biomarkers, Lupus Coagulation Inhibitor, Antiphospholipid Syndrome
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