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A prothrombin time-based functional assay of protein S
L Preda1, A Tripodi, C Valsecchi
1R & D Instrumentation Laboratory S.p.A., Milano, Italy.
Thrombosis Research
|October 1, 1990
Summary
This study presents a new assay to measure protein S activity, crucial for blood clotting. The assay is sensitive and reproducible, making it ideal for screening protein S deficiencies.
Area of Science:
- Biochemistry
- Hematology
- Clinical Diagnostics
Background:
- Protein S is a vital cofactor for activated protein C, regulating blood coagulation.
- Deficiencies in Protein S activity are linked to thrombotic disorders.
- Accurate measurement of Protein S activity is essential for diagnosing and managing these conditions.
Purpose of the Study:
- To develop and validate a sensitive and reproducible assay for measuring protein S activity.
- To assess the suitability of the assay for screening congenital and acquired protein S deficiency.
Main Methods:
- A prothrombin time-based clotting assay was utilized.
- The assay involved mixing diluted plasma samples with protein S-depleted plasma, activated protein C (via Protac), thromboplastin, and calcium ions.
- Assay specificity was confirmed through dose-dependency studies and testing patient samples.
Main Results:
- The assay demonstrated a direct correlation between clotting time prolongation and protein S activity.
- Specificity was confirmed by the dependence on protein S and validation with known patient conditions.
- The assay exhibited high sensitivity and reproducibility, with an interassay coefficient of variation below 5%.
Conclusions:
- The developed assay is a reliable method for quantifying protein S activity.
- Its sensitivity, reproducibility, and ease of use make it suitable for screening both congenital and acquired protein S deficiencies.
- This assay can aid in the diagnosis and management of thrombotic disorders related to protein S dysfunction.