Comparison of Three Methods for Measuring Factor VIII Levels in Plasma
Abstract
We compared 1-stage clot-based, chromogenic, and immunoassay methods for measuring factor VIII in plasma with a focus on the measurement of elevated levels of factor VIII. The chromogenic assay showed the best interassay imprecision for factor VIII levels near 150 IU/dL. The best correlation was between the 1-stage clot-based and chromogenic factor VIII assays (r2 = 0.934), and the lowest correlation was between the 1-stage clot-based and antigenic factor VIII assays (r2 = 0.821). The presence of heparin, low-molecular-weight heparin, lepirudin, or lupus inhibitors in the sample resulted in major interference in the 1-stage clot-based assay but not the chromogenic or antigenic factor VIII assays. Overall, the chromogenic factor VIII activity assay was the optimal method, showing good precision, the best overall correlation with other assays, and no interference from heparin, low-molecular-weight heparin, lepirudin, or lupus inhibitors.
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Other coagulation assays that use aPTT-based methods may show interference due to LA presence, resulting in falsely low factor activity.
“Other coagulation assays that use aPTT-based methods, as one stage measurement (OSA) [90] for factors VIII, IX, XI, and XII, may show interference due to LA presence, resulting in falsely low factor activity [91,92,93,94,95,96,97,98].”
From Lupus Anticoagulant Detection under the Magnifying Glass (2023) · cites this paper as [96]
Chromogenic factor assays (CSA) do not suffer from these interferences, showing normal clotting factor activities.
“A fundamental aid in these circumstances comes from performing chromogenic factor assays (CSA) [90], which do not suffer from these interferences, showing normal clotting factor activities [92,96,97].”
From Lupus Anticoagulant Detection under the Magnifying Glass (2023) · cites this paper as [96]
Cites
Koster, T., Vandenbroucke, J. P., Rosendaal, F. R., Briët, E., Rosendaal, F. R., & Blann, A. D. (1995) · The Lancet · doi:10.1016/s0140-6736(95)90166-3 · Cited by 1,131 · see citing works
High plasma levels of factor VIII and the risk of recurrent venous thromboembolism
Kyrle, P. A., Minar, E., Hirschl, M., Bialonczyk, C., Stain, M., Schneider, B., Weltermann, A., Speiser, W., Lechner, K., & Eichinger, S. (2000) · New England Journal of Medicine · doi:10.1056/nejm200008173430702 · Cited by 763 · see citing works
High Plasma Concentration of Factor VIIIc Is a Major Risk Factor for Venous Thromboembolism
Anker, P. I. '., Koopman, M. M. W., Reitsma, P. H., Prins, M. H., van den Ende, A., Buller, H. R., & Kraaijenhagen, R. A. (2000) · Thrombosis and Haemostasis · doi:10.1055/s-0037-1613747 · Cited by 490 · see citing works
Kamphuisen, P. W., Eikenboom, J. C. J., Vos, H. L., Pablo, R. F., Sturk, A., Rosendaal, F. R., & Bertina, R. M. (1999) · Thrombosis and Haemostasis · doi:10.1055/s-0037-1614553 · Cited by 259 · see citing works
Laposata, M., Green, D., Cott, E. M. V., Barrowcliffe, T. W., Goodnight, S. H., & Sosolik, R. C. (1998) · PubMed · Cited by 249 · see citing works
Mumford, A. D., Manning, R., Laffan, M., & O’Donnell, J. (2000) · Thrombosis and Haemostasis · doi:10.1055/s-0037-1613748 · Cited by 208 · see citing works
A Hexagonal (II) Phase Phospholipid Neutralization Assay for Lupus Anticoagulant Identification
Triplett, D. A., Barna, L. K., & Unger, G. A. (1993) · Thrombosis and Haemostasis · doi:10.1055/s-0038-1649671 · Cited by 132 · see citing works
Factor V Antigen Levels and Venous Thrombosis
Kamphuisen, P. W., Rosendaal, F. R., Eikenboom, J. C. J., Bos, R., & Bertina, R. M. (2000) · Arteriosclerosis Thrombosis and Vascular Biology · doi:10.1161/01.atv.20.5.1382 · Cited by 66 · see citing works
Mitrio, V. D., Marino, R., Scaraggi, F. A., Bari, L. D., Giannoccaro, F., Petronelli, M., Ranieri, P., Tannoia, N., & Schiraldi, O. (1999) · Blood Coagulation & Fibrinolysis · doi:10.1097/00001721-199910000-00002 · Cited by 23 · see citing works
Cap survey results for factor VIII assays (1977-1978).
Kocoshis, T. A., & Triplett, D. A. (1979) · PubMed · Cited by 23 · see citing works
Thompson, S. G., Duckert, F., Haverkate, F., & THOMSON, J. M. (1989) · Thrombosis and Haemostasis · doi:10.1055/s-0038-1646581 · Cited by 23 · see citing works
Arkin, C. F., BOVILL, E. G., Brandt, J. T., Rock, W. A., & Triplett, D. A. (1992) · PubMed · Cited by 17 · see citing works
Lethagen, S., Østergaard, H., & Nilsson, I. M. (1986) · Scandinavian Journal of Haematology · doi:10.1111/j.1600-0609.1986.tb02636.x · Cited by 16 · see citing works
Kleinveld, H. A., Andersson, N.-E., van Voorthuizen, H., den Hartog, J., & de Groot, P. G. (1999) · Scandinavian Journal of Clinical and Laboratory Investigation · doi:10.1080/00365519950185526 · Cited by 11 · see citing works
Hutton, R. A., Yamaga, A. K., Matthews, K. B., & Woodhams, B. J. (1991) · Thrombosis Research · doi:10.1016/0049-3848(91)90281-z · Cited by 4 · see citing works
Flagged first, then by citations
1 of the 16 references couldn’t be matched to a known paper.
Cited by
Sorted by citations
The past and future of haemophilia: diagnosis, treatments, and its complications
Peyvandi, F., Garagiola, I., & Young, G. (2016) · The Lancet · doi:10.1016/s0140-6736(15)01123-x · Cited by 505 · see citing works
International Recommendations on the Diagnosis and Treatment of Acquired Hemophilia A
Tiede, A., Collins, P., Knoebl, P., Teitel, J., Kessler, C., Shima, M., Di Minno, G., d’Oiron, R., Salaj, P., Jiménez-Yuste, V., et al. (2020) · Haematologica · doi:10.3324/haematol.2019.230771 · Cited by 401 · see citing works
Risk assessment for recurrent venous thrombosis
Kyrle, P. A., Rosendaal, F. R., & Eichinger, S. (2010) · The Lancet · doi:10.1016/s0140-6736(10)60962-2 · Cited by 263 · see citing works
A critical appraisal of one‐stage and chromogenic assays of factor VIII activity
Peyvandi, F., Oldenburg, J., & Friedman, K. D. (2015) · Journal of Thrombosis and Haemostasis · doi:10.1111/jth.13215 · Cited by 155 · see citing works
Improvements in Factor VIII Inhibitor Detection: From Bethesda to Nijmegen
Verbruggen, B., van Heerde, W. L., & Gorkom, B. A. P. L. (2009) · Seminars in Thrombosis and Hemostasis · doi:10.1055/s-0029-1245107 · Cited by 78 · see citing works
Miller, C. H., Rice, A. S., Boylan, B., Shapiro, A. D., Lentz, S. R., Wicklund, B. M., Kelly, F. M., & Soucie, J. M. (2013) · Journal of Thrombosis and Haemostasis · doi:10.1111/jth.12259 · Cited by 62 · see citing works
Acquired Hemophilia A: Current Guidance and Experience from Clinical Practice
Pishko, A. M., & Doshi, B. S. (2022) · Journal of Blood Medicine · doi:10.2147/jbm.s284804 · Cited by 59 · see citing works
Diagnosis and quantification of factor VIII inhibitors
Verbruggen, B. (2009) · Haemophilia · doi:10.1111/j.1365-2516.2008.01924.x · Cited by 50 · see citing works
Chromogenic factor VIII activity assay
Moser, K. A., & Funk, D. M. A. (2014) · American Journal of Hematology · doi:10.1002/ajh.23723 · Cited by 45 · see citing works
Adcock, D. M., Strandberg, K., Shima, M., & Marlar, R. A. (2018) · International Journal of Laboratory Hematology · doi:10.1111/ijlh.12877 · Cited by 40 · see citing works
Diagnosis of factor VIII deficiency
Verbruggen, B., Meijer, P., Nováková, I. R. O., & van Heerde, W. L. (2008) · Haemophilia · doi:10.1111/j.1365-2516.2008.01715.x · Cited by 38 · see citing works
The “normal” factor VIII concentration in plasma
Butenas, S., Parhami-Seren, B., Undas, A., Fass, D. N., & Mann, K. G. (2010) · Thrombosis Research · doi:10.1016/j.thromres.2010.04.004 · Cited by 30 · see citing works
Rodgers, S., DUNCAN, E. M., Sobieraj‐Teague, M., & Lloyd, J. V. (2009) · International Journal of Laboratory Hematology · doi:10.1111/j.1751-553x.2007.01021.x · Cited by 28 · see citing works
Ninivaggi, M., Dargaud, Y. G., van Oerle, R., de Laat, B., Hemker, H. C., & Lindhout, T. (2011) · Journal of Thrombosis and Haemostasis · doi:10.1111/j.1538-7836.2011.04358.x · Cited by 28 · see citing works
Szlam, F., Sreeram, G. M., Solomon, C., Levy, J. H., Molinaro, R. J., & Tanaka, K. A. (2010) · Thrombosis Research · doi:10.1016/j.thromres.2010.10.017 · Cited by 23 · see citing works
Diurnal variation of von W illebrand factor in plasma: the B ispebjerg study of diurnal variations
Timm, A., Fahrenkrug, J., Jørgensen, H. L., Sennels, H. P., & Goetze, J. P. (2014) · European Journal Of Haematology · doi:10.1111/ejh.12298 · Cited by 20 · see citing works
Role of chromogenic assays in haemophilia A and B diagnosis
Bowyer, A. E., Duncan, E. M., & Antović, J. P. (2018) · Haemophilia · doi:10.1111/hae.13520 · Cited by 19 · see citing works
Gidaro, A., Palmieri, G., Donadoni, M., Mameli, L., Cava, L. L., Sanna, G. D., Castro, D. D., Delitala, A., Manetti, R., & Castelli, R. (2022) · Diagnostics · doi:10.3390/diagnostics12102559 · Cited by 16 · see citing works
Bosch, A., Uleryk, E. M., & Avila, L. (2023) · Research and Practice in Thrombosis and Haemostasis · doi:10.1016/j.rpth.2023.100064 · Cited by 14 · see citing works
Avoiding errors in the laboratory evaluation of potent lupus anticoagulants
Penmetsa, G. K., Rodgers, G. M., & Smock, K. J. (2010) · American Journal of Hematology · doi:10.1002/ajh.21666 · Cited by 14 · see citing works
Issues complicating precision dosing for factor VIII prophylaxis
Valentino, L. A., Turecek, P. L., Gritsch, H., Butenas, S., & Mann, K. G. (2018) · Transfusion and Apheresis Science · doi:10.1016/j.transci.2018.07.007 · Cited by 11 · see citing works
Thermolability of factor VIII in donor fresh frozen blood plasma
Нодарович, Л. В., Чечеткин, А. В., Гудков, А. Г., Leushin, V. Y., Дмитриевич, К. А., & KISELEVA, E. A. (2021) · Гематология и трансфузиология · doi:10.35754/0234-5730-2021-66-4-593-609 · Cited by 10 · see citing works
Lupus Anticoagulant Detection under the Magnifying Glass
Molinari, A. C., Martini, T., Banov, L., Ierardi, A., Leotta, M., Strangio, A., & Santoro, R. C. (2023) · Journal of Clinical Medicine · doi:10.3390/jcm12206654 · Cited by 9 · see citing works
Diagnosis and laboratory monitoring of acquired hemophilia A
Platton, S., Sivapalaratnam, S., & Raheja, P. (2023) · Hematology · doi:10.1182/hematology.2023000460 · Cited by 9 · see citing works
The dos, don'ts, and nuances of thrombophilia testing
Chiasakul, T., & Bauer, K. A. (2023) · Hematology · doi:10.1182/hematology.2023000491 · Cited by 9 · see citing works
Assay of Factor VIII and Other Clotting Factors
Kitchen, S., & Preston, F. E. (2013) · Wiley eBooks · doi:10.1002/9781118543467.ch10 · Cited by 9 · see citing works
Bezaire, J., Thomson, D., & McNair, E. (2018) · Journal of ExtraCorporeal Technology · doi:10.1051/ject/201850170 · Cited by 8 · see citing works
Evaluation of Factor VIII as a Risk Factor in Indian Patients with DVT
Hazra, D., Sen, I., Stephen, E., Agarwal, S. K., Nair, S. C., & Mammen, J. (2015) · Surgery Research and Practice · doi:10.1155/2015/307879 · Cited by 6 · see citing works
McEneny‐King, A., Chelle, P., Iorio, A., & Edginton, A. N. (2018) · Thrombosis Research · doi:10.1016/j.thromres.2018.08.004 · Cited by 6 · see citing works
Congenital Bleeding Disorders: Diagnosis and Management
Dorgalaleh, A., Daneshi, M., Dabbagh, A., & Crookston, K. P. (2023) · Springer eBooks · doi:10.1007/978-3-031-43156-2_2 · Cited by 6 · see citing works
Amrani, M. E., Donners, A. A. M. T., Graat, G. H. M., Lentjes, E. G. W. M., Huisman, A., Musson, R. E. A., & van Maarseveen, E. M. (2019) · Journal of Pharmaceutical and Biomedical Analysis · doi:10.1016/j.jpba.2019.112781 · Cited by 5 · see citing works
Factor VIII Inhibitor Assays: Methodology, Shortcomings, and Challenges
van Geffen, M., Dardikh, M., & Verbruggen, B. (2009) · Cited by 5 · see citing works
Tykhomyrov, A. A., Nedzvetsky, V. S., Shemet, S. A., & Ağca, C. A. (2017) · TURKISH JOURNAL OF BIOLOGY · doi:10.3906/biy-1704-10 · Cited by 5 · see citing works
Method validation and clinical utility of chromogenic factor VIII assay compared to one-stage assay
Gouws, W., Botha, E., & Visser, A. (2013) · Journal of Thrombosis and Thrombolysis · doi:10.1007/s11239-013-0910-3 · Cited by 4 · see citing works
Omidkhoda, A., Tabatabaei, M. R., Atarodi, K., Karimi, K., Froushani, A. R., & Pourfathollah, A. A. (2011) · Europe PMC (PubMed Central) · doi:10.2450/2011.0064-10 · Cited by 4 · see citing works
Favaloro, E. J., & Pasalic, L. (2022) · Research and Practice in Thrombosis and Haemostasis · doi:10.1002/rth2.12689 · Cited by 4 · see citing works
Crighton, G. L. (2013) · Methods in molecular biology · doi:10.1007/978-1-62703-339-8_5 · Cited by 4 · see citing works
Detecting and Quantifying Functional Inhibitors in Hemostasis
Verbruggen, B., Nováková, I. R. O., & van Heerde, W. L. (2008) · Wiley eBooks · doi:10.1002/9781444303575.ch20 · Cited by 4 · see citing works
Xu, C., Du, Z., Hu, G., Ma, Y., & Li, C. (2024) · Clinica Chimica Acta · doi:10.1016/j.cca.2024.119950 · Cited by 3 · see citing works
Chen, V., Roby, L. C., Wentzel, S., Li, M., & Jones, N. (2022) · Journal of Medical Case Reports · doi:10.1186/s13256-022-03402-x · Cited by 3 · see citing works
Gholami, M. S., Valikhani, M., Dorgalaleh, A., Mousavi, S. H., & Pezeshkpoor, B. (2018) · Springer eBooks · doi:10.1007/978-3-319-76723-9_4 · Cited by 3 · see citing works
Patil, R., S., C., Parihar, A., Mohite, A., & Shetty, S. (2018) · Thrombosis Research · doi:10.1016/j.thromres.2018.10.015 · Cited by 2 · see citing works
Genç, S., Aydin, A. F., Karaca, E., & Ömer, B. (2019) · International Journal of Laboratory Hematology · doi:10.1111/ijlh.13036 · Cited by 2 · see citing works
Vinholt, P. J., & Nybo, M. (2014) · Blood Coagulation & Fibrinolysis · doi:10.1097/mbc.0000000000000240 · Cited by 2 · see citing works
Plasma Factor VIII Levels as a Biomarker for Venous Thromboembolism
Bittar, L. F., Paula, E. V. D., Barnabé, A., Mazetto, B. D. M., Zapponi, K. C. S., Montalvão, S. A. D. L., Colella, M. P., Orsi, F. A., & Annichino‐Bizzacchi, J. M. (2015) · Springer eBooks · doi:10.1007/978-94-007-7741-5_22-1 · Cited by 2 · see citing works
Detecting and Quantifying Acquired Functional Inhibitors in Hemostasis
Verbruggen, B., Dardikh, M., & Gorkom, B. A. P. L. (2013) · Wiley eBooks · doi:10.1002/9781118543467.ch12 · Cited by 2 · see citing works
Factor VIII Methods: Which Assay Principle for which Indication?
Peetz, D. (2007) · Springer eBooks · doi:10.1007/978-3-540-36715-4_12 · Cited by 2 · see citing works
Misleading one-stage coagulation factor assay during rFVIIa treatment in lupus patient
HERBERS, A. H. E., VERBRUGGEN, B., VAN DE VEERDONK, F., VAN KRAAIJ, M., BLIJLEVENS, N. M. A., & NOVAKOVA, I. R. O. (2009) · Haemophilia · doi:10.1111/j.1365-2516.2009.02061.x · Cited by 1 · see citing works
REHABILITASI MEDIK PADA HEMOFILIA
Yoshua, V., & Angliadi, E. (2013) · Jurnal Biomedik JBM · doi:10.35790/jbm.5.2.2013.2587 · Cited by 1 · see citing works
Hemophilia A: Diagnosis and Management
Kaya, Z., Safarian, N., Pezeshkpoor, B., & Adcock, D. M. (2023) · Springer eBooks · doi:10.1007/978-3-031-43156-2_4 · Cited by 1 · see citing works
Youssef, I., Abuelela, S. A., & Hamza, W. (2019) · HAL · Cited by 1 · see citing works
Plasma Factor VIII Levels as a Biomarker for Venous Thromboembolism
Bittar, L. F., Paula, E. V. D., Barnabé, A., Mazetto, B. D. M., Zapponi, K. C. S., Montalvão, S. A. D. L., Colella, M. P., Orsi, F. A., & Annichino‐Bizzacchi, J. M. (2016) · Springer eBooks · doi:10.1007/978-94-007-7678-4_22 · Cited by 1 · see citing works
Clotting Factors and Inhibitors: Assays and Interpretation
Meijer, P., Verbruggen, H. W., & Spannagl, M. (2012) · Wiley eBooks · doi:10.1002/9781444398595.ch33
Laboratory and Quality Control of Assays
Kitchen, S. (2014) · Wiley eBooks · doi:10.1002/9781118398258.ch43
Dücker, C. (2012) · Universitätsbibliothek der FU Berlin Hochschulschriftenstelle u. Dokumentenserver · doi:10.17169/refubium-17207
Vinzio, S., Desprez, D., Tharin, C., Schlienger, J.-L., Grunebaum, L., & Goichot, B. (2008) · La Revue de Médecine Interne · doi:10.1016/j.revmed.2008.03.245
Omidkhoda, A., Tabatabaei, M., Atarodi, K., & Karimi, K. (2011) · Scientific Journal of Iran Blood Transfus Organ
Origin and Role of Factor Viia
Khandekar, G. (2013) · doi:10.12794/metadc407814
Laboratory Evaluation of Long-Term Thrombophilic Disorders
Roshal, M. (2013) · Elsevier eBooks · doi:10.1016/b978-0-12-397164-7.00143-9
Quality Management of Hematology Tests in Blood Center
Kim, H., & Hur, M. (2017) · The Korean Journal of Blood Transfusion · doi:10.17945/kjbt.2017.28.1.13
Sugimoto, T., Morimoto, K., Hashimoto, H., Kaneda, Y., Ohata, S., & Yasutomo, Y. (2018) · Acta Haematologica Polonica · doi:10.2478/ahp-2018-0007
Educational Case: The Bleeding Patient
McCool, I. E., Muir, J. M., & Knollmann-Ritschel, B. E. C. (2019) · Academic Pathology · doi:10.1177/2374289519886042
Pharmacokinetic modelling of clinically relevant situations in the treatment of hemophilia A and B
McEneny‐King, A. (2020) · UWSpace (University of Waterloo)
Chromogenic assay in hemopihilia treatment
OGAWA, M., Suzuki, A., Suzuki, N., & NAKAYAMA, T. (2022) · Japanese Journal of Thrombosis and Hemostasis · doi:10.2491/jjsth.33.75
Laboratory Evaluation of Long-Term Thrombophilic Disorders
Roshal, M., & Gil, M. R. (2018) · Elsevier eBooks · doi:10.1016/b978-0-12-813726-0.00147-1
Міжнародні рекомендації з діагностики та лікування набутої гемофілії А*
(2022) · Український медичний часопис · doi:10.32471/umj.1680-3051.149.230792
Management of head and neck tumors in patients with Haemophilia A. A Case report
Bourazani, M., Kouroumalis, A., Kolomvos, N., & Kalfarantzos, E. (2022) · Hellenic Archives of Oral and Maxillofacial Surgery · doi:10.54936/haoms232127131
Innovative drug monitoring of factor VIII and emicizumab in haemophilia A
Donners, A. A. M. T. (2023) · doi:10.33540/1772
MacNeill, M., Mansory, E. M., Lazo‐Langner, A., & Phua, C. W. W. (2023) · Cureus · doi:10.7759/cureus.41029
Нодарович, Л. В., Sidorkevich, S. V., & Дмитриевич, К. А. (2024) · Гематология и трансфузиология · doi:10.35754/0234-5730-2024-69-1-32-39
Elevated factor VIII level in cerebral venous thrombosis: a case-control study
Bhagwan, B., Pillay, M., Schutte, C.-M., Masenge, A., & Kakaza, M. (2024) · Wits Journal of Clinical Medicine · doi:10.18772/26180197.2024.v6n2a2
Liu, L., & Guo, D. (2026) · Frontiers in Immunology · doi:10.3389/fimmu.2026.1735963
Gatt, A., Riva, N., Sammut, L., Vella, K., Kitchen, S., Hickey, K. P., & Borg-Aquilina, D. (2026) · Seminars in Thrombosis and Hemostasis · doi:10.1055/a-2971-6729
- Authors
- Chandler, W. L., Ferrell, C., Lee, J., Tun, T., & Kha, H.
- Affiliations
- University of Washington (US)
- Venue
- American Journal of Clinical Pathology
- Publisher
- Oxford University Press (OUP)
- Published
- 2003-07
- Volume
- 120
- Issue
- 1
- Pages
- 34-39
- ISSN
- 0002-9173 (ISSN-L)
- 1943-7722
- OpenAlex
- W4247774385
- Cited by
- 74
- References
- 16
- Citations by year
- 2026: 2 · 2024: 4 · 2023: 8 · 2022: 7 · 2021: 1 · 2020: 2 · 2019: 4 · 2018: 9 · 2017: 2 · 2016: 2 · 2015: 3 · 2014: 4 · 2013: 8 · 2012: 2
- FWCI
- 0.00
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- American Journal of Clinical Pathology (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Hematology › Hemophilia Treatment and Research
- Health Sciences › Medicine › Hematology › Platelet Disorders and Treatments
- Health Sciences › Medicine › Physiology › Clinical Laboratory Practices and Quality Control
- Keywords
- factor VIII, chromogenic assay, immunoassay, assay comparison, assay interference, heparin, low molecular weight heparin, lepirudin, lupus anticoagulant, assay precision
- MeSH terms
- Blood Coagulation, Blood Coagulation Tests, Chromogenic Compounds, Factor VII, Humans, Immunoassay, Reagent Kits, Diagnostic, Reproducibility of Results
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