Solid-phase immunoradiometric assay of factor-VIII protein.

Area of Science:

• Biochemistry
• Immunology
• Hematology

Background:

• Factor-VIII protein is crucial for blood coagulation.
• Accurate measurement of factor-VIII is essential for diagnosing bleeding disorders like hemophilia A and von Willebrand disease.
• Existing immunoassays for factor-VIII often lack sufficient sensitivity or specificity.

Purpose of the Study:

• To develop a highly sensitive and specific solid-phase immunoradiometric assay for quantifying factor-VIII protein.
• To evaluate the assay's performance in plasma samples from individuals with hemophilia A and von Willebrand disease.

Main Methods:

• Development of a solid-phase immunoradiometric assay using 125I-labeled rabbit anti-factor VIII antibody.
• Isolation of specific anti-factor VIII antibody via immunoadsorbent chromatography.
• Incubation of plasma samples in antibody-coated tubes followed by addition of labeled antibody and counting.

Main Results:

• The assay demonstrated high sensitivity, measuring concentrations as low as 0.16 ng of factor-VIII.
• Normal factor-VIII levels were observed in pooled normal human plasma (8 microgram/ml).
• Reduced factor-VIII concentrations were detected in von Willebrand disease plasma, while hemophilia A plasma showed normal levels.

Conclusions:

• The developed assay offers improved sensitivity, specificity, efficiency, and economy compared to previous methods.
• This assay is a valuable tool for the accurate quantification of factor-VIII protein.
• The assay aids in the differential diagnosis of bleeding disorders by detecting characteristic factor-VIII levels.