Preparation of a purified fibrinogen calibration material for Clauss method and turbidimetric immunoassay possessing biological activity and antigenicity.

摘要

Fibrinogen plays a major role in basic coagulation tests such as prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT). These show high interlaboratory variation because of inaccurate instrumental calibration. The same is true of the fibrinogen assay, despite its being a quantitative assay. Most medical laboratories use automated coagulometers and commercially available calibration materials (calibrators) to obtain an accurate fibrinogen value, but, when checked, calibrators have been found to deviate from the assigned value. The Japan Society of Laboratory Medicine (JSLM) has identified the need for a reliable plasma fibrinogen standard. To enhance the reliability of calibrator fibrinogen values and thereby remedy the poor precision and accuracy of plasma fibrinogen testing, we undertook the preparation of a standard calibration material applicable to both the Clauss method and turbidimetric immunoassay (TIA). The calibrator was prepared from fresh human plasma by glycine precipitation and virus inactivation followed by affinity chromatography to remove contaminated plasminogen. In the resulting product, clottable fibrinogen accounted for 95% of total protein and within-run precision showed a CV of less than 1.8%. We believe the preparation will become a candidate material for laboratory and manufacturer use in Japan.