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In vitro kinetics of factor VIII activity in patients with mild haemophilia A and a discrepancy between one-stage and two-stage factor VIII assay results.
Br J Haematol. 2007 Jan; 136(1):138-45.BJ

Abstract

In some mild haemophilia A patients (discrepant haemophilia), factor VIII coagulant activity (FVIII:C) levels, by one-stage assay are more than double than those by two-stage assay. This may be due to the longer incubation times (10-12 min) in the two-stage assay. This study aimed to determine the time course of the activation phase of the two-stage assay, using both classical coagulation and chromogenic detection methods. In both systems, for equivalent patients (equivalent FVIII:C levels by one-stage and two-stage assays, n = 6, all different mutations), similar FVIII:C results were obtained with short- or long-incubation times. In contrast, plasma from discrepant patients (n = 8, five different mutations) showed higher FVIII:C at shorter incubation times than after longer incubation times. In the chromogenic assay, FVIII:C levels were higher after incubation for 2 min (23-56%, mean 41%) than after 10 min (19-41%, mean 29%). In the classical coagulation assay, FVIII:C levels were higher at shorter incubation times (21-64%, mean 37%) than with the longer incubation times usually used (13-29%, mean 23%). These time-course experiments have verified that the longer incubation time used in the two-stage assay is at least partly responsible for the lower FVIII:C measured by that assay in discrepant haemophilia.

Authors+Show Affiliations

Haematology Division, Institute of Medical and Veterinary Science, University of South Australia, Adelaide, Australia. susan.rodgers@imvs.sa.gov.auNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17222201

Citation

Rodgers, Susan E., et al. "In Vitro Kinetics of Factor VIII Activity in Patients With Mild Haemophilia a and a Discrepancy Between One-stage and Two-stage Factor VIII Assay Results." British Journal of Haematology, vol. 136, no. 1, 2007, pp. 138-45.
Rodgers SE, Duncan EM, Barbulescu DM, et al. In vitro kinetics of factor VIII activity in patients with mild haemophilia A and a discrepancy between one-stage and two-stage factor VIII assay results. Br J Haematol. 2007;136(1):138-45.
Rodgers, S. E., Duncan, E. M., Barbulescu, D. M., Quinn, D. M., & Lloyd, J. V. (2007). In vitro kinetics of factor VIII activity in patients with mild haemophilia A and a discrepancy between one-stage and two-stage factor VIII assay results. British Journal of Haematology, 136(1), 138-45.
Rodgers SE, et al. In Vitro Kinetics of Factor VIII Activity in Patients With Mild Haemophilia a and a Discrepancy Between One-stage and Two-stage Factor VIII Assay Results. Br J Haematol. 2007;136(1):138-45. PubMed PMID: 17222201.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - In vitro kinetics of factor VIII activity in patients with mild haemophilia A and a discrepancy between one-stage and two-stage factor VIII assay results. AU - Rodgers,Susan E, AU - Duncan,Elizabeth M, AU - Barbulescu,Denise M, AU - Quinn,Diana M, AU - Lloyd,John V, PY - 2007/1/16/pubmed PY - 2007/3/29/medline PY - 2007/1/16/entrez SP - 138 EP - 45 JF - British journal of haematology JO - Br J Haematol VL - 136 IS - 1 N2 - In some mild haemophilia A patients (discrepant haemophilia), factor VIII coagulant activity (FVIII:C) levels, by one-stage assay are more than double than those by two-stage assay. This may be due to the longer incubation times (10-12 min) in the two-stage assay. This study aimed to determine the time course of the activation phase of the two-stage assay, using both classical coagulation and chromogenic detection methods. In both systems, for equivalent patients (equivalent FVIII:C levels by one-stage and two-stage assays, n = 6, all different mutations), similar FVIII:C results were obtained with short- or long-incubation times. In contrast, plasma from discrepant patients (n = 8, five different mutations) showed higher FVIII:C at shorter incubation times than after longer incubation times. In the chromogenic assay, FVIII:C levels were higher after incubation for 2 min (23-56%, mean 41%) than after 10 min (19-41%, mean 29%). In the classical coagulation assay, FVIII:C levels were higher at shorter incubation times (21-64%, mean 37%) than with the longer incubation times usually used (13-29%, mean 23%). These time-course experiments have verified that the longer incubation time used in the two-stage assay is at least partly responsible for the lower FVIII:C measured by that assay in discrepant haemophilia. SN - 0007-1048 UR - https://www.unboundmedicine.com/medline/citation/17222201/In_vitro_kinetics_of_factor_VIII_activity_in_patients_with_mild_haemophilia_A_and_a_discrepancy_between_one_stage_and_two_stage_factor_VIII_assay_results_ L2 - https://doi.org/10.1111/j.1365-2141.2006.06402.x DB - PRIME DP - Unbound Medicine ER -