Chromogenic factor VIII activity assay

Chromogenic determination of factor VIII activity in plasma and factor VIII concentrates

Discrepancy between one-stage and chromogenic factor VIII activity assay results can lead to misdiagnosis of haemophilia A phenotype.

UNLABELLED Severity of bleeding phenotype in hemophilia A (HA) depends on the underlying mutation in the F8 gene and, ultimately, on the concentration and functional integrity of the factor VIII (FVIII) protein in circulating plasma. Initial diagnosis for HA and monitoring of treatment is typically performed by measuring of FVIII activity by either one-stage assay or chromogenic assay. We revie...

Chromogenic Factor IX Assay for Clinical Use

A chromogenic factor IX assay is developed which requires only two timedependent steps. Diluted plasma is mixed with a reagent containing factors VIII and X. The reaction is started by addition of a reagent containing factor XI", thrombin, CaCl2, and phospholipids. Then factor XIu activates factor IX if present, thrombin activates factor VIII, and subsequently the complete factor X activating c...

A critical appraisal of one-stage and chromogenic assays of factor VIII activity.

Accurate and precise potency determination by manufacturers of different types of factor VIII product (plasma-derived and recombinant FVIII [rFVIII]) is vital to clinicians and patients using FVIII concentrates. A separate, but related, requirement is ascertaining the FVIII activity levels in clinical samples for diagnosing and treating hemophilia A. The one-stage clotting assay (OSA) and the c...

Biological Activity Analysis of Native and Recombinant Streptokinase Using Clot Lysis and Chromogenic Substrate Assay

Determination of streptokinase activity is usually accomplished through two assay methods: a) Clot lysis, b) Chromogenic substrate assay. In this study the biological activity of two streptokinase products, namely Streptase®, which is a native product and Heberkinasa®, which is a recombinant product, was determined against the third international reference standard using the two forementioned a...