Automation of two-stage factor VIII assay

Area of Science:

• Clinical Chemistry
• Hematology
• Biotechnology

Background:

• Accurate quantification of factor VIII (FVIII) is crucial for diagnosing and managing bleeding disorders.
• Automated assays offer efficiency and reproducibility in clinical laboratories.

Purpose of the Study:

• To compare the performance of two automated two-stage factor VIII assays: Depex and Electra.
• To evaluate their suitability for routine clinical use, including assays of factor VIII concentrates.

Main Methods:

• The Depex method utilizes an electrical circuit completion for clot detection.
• The Electra method employs an optical density technique for clot detection.
• Both methods were compared using haemophilic and normal plasma samples, as well as factor VIII concentrates.

Main Results:

• Both Depex and Electra provided comparable factor VIII levels for haemophilic and normal plasmas.
• Both methods are considered valid for low and normal factor VIII levels.
• Electra is suitable for factor VIII concentrate assays, whereas Depex may produce falsely elevated results due to increased viscosity.

Conclusions:

• Both automated assays are reliable for plasma factor VIII determination.
• Electra demonstrates broader applicability, including accurate quantification of factor VIII concentrates.
• Depex's limitations with viscous samples necessitate careful consideration in concentrate analysis.