The utility of activated partial thromboplastin time (aPTT) clot waveform analysis in the investigation of hemophilia A patients with very low levels of factor VIII activity (FVIII:C)

Thromb Haemost. 2002 Mar;87(3):436-41.

Abstract

The lower detection limit of the conventional one-stage aPTT based clotting assay for determining FVIII:C levels is generally 1.0-2.0 IU/dl. Consequently, it has been impossible to study the clinical significance of levels of FVIII:C less than 1.0 IU/dl. Using a photo-optical automated coagulation analyzer, the Organon Teknika MDA II, we have performed qualitative and quantitative aPTT waveform analysis and measured FVIII:C levels by automated one-stage aPTT clotting assay in 36 severely affected Hemophilia A patients. Qualitative waveform analysis showed clear evidence of individual differences in the waveform profile suggesting differing coagulant activity from patient to patient. The FVIII:C level was less than 0.2 IU/dl in 23 cases and levels of FVIII:C between 0.2 and 1.0 IU/dl could be discriminated in 13 patients. The FVIII:C level in these patients was closely correlated with the minimum value of the second derivative of the aPTT waveform (Min2). This is a measure of the acceleration of change in optical transmission at the initiation of coagulation. Furthermore, the correlation of the

Publication types

  • Evaluation Study

MeSH terms

  • Blood Coagulation Tests / instrumentation
  • Blood Coagulation Tests / standards
  • Factor VIII / analysis*
  • Hemophilia A / blood
  • Hemophilia A / diagnosis
  • Humans
  • Kinetics
  • Partial Thromboplastin Time
  • Reference Values
  • Sensitivity and Specificity

Substances

  • Factor VIII