One-stage and chromogenic FVIII:C assay discrepancy in mild haemophilia A and the relationship with the mutation and bleeding phenotype

Haemophilia. 2008 Sep;14(5):1049-54. doi: 10.1111/j.1365-2516.2008.01781.x. Epub 2008 Jun 5.


The discrepancy of the levels of factor VIII activity (FVIII:C) by different assays in some mild and moderate haemophilic A patients has been long known. Specific mutations affecting FVIII:C discrepancies have been described. No consensus exit as to which method most accurately represents the FVIII cofactor function in vivo and which has a better correlation with the haemorrhagic clinical expression. We studied 163 mild A haemophiliacs, and detected discrepancies in 20% of the patients, most of whom presented higher levels of FVIII:C with the one-stage assay. In nine families, the FVIII mutation was found, while three showed mutations not previously described (Leu1978Phe and Ser1791Pro associated with higher levels of FVIII:C by one-stage method; Arg1639His in a patient with low level of FVIII:C by the one-stage, but normal, chromogenic assay). Assessing the level of FVIII:C by different methods could help to learn the possible haemorrhagic expressions of patients.

MeSH terms

  • Adolescent
  • Adult
  • Blood Coagulation Tests / methods
  • Child
  • Chromogenic Compounds
  • Factor VIII / genetics
  • Factor VIII / metabolism*
  • Hemophilia A / blood*
  • Hemophilia A / complications
  • Hemophilia A / genetics
  • Hemorrhage / blood
  • Hemorrhage / etiology
  • Hemorrhage / genetics
  • Humans
  • Male
  • Middle Aged
  • Mutation*
  • Phenotype
  • Reproducibility of Results
  • Young Adult


  • Chromogenic Compounds
  • Factor VIII