Performance characteristics of fibrinogen assays. Results of the College of American Pathologists Proficiency Testing Program 1988-1991.

Plasma fibrinogen concentration appears to be an important risk factor for the development of atherosclerotic cardiovascular disease of a similar magnitude to cholesterol. The quality control of plasma fibrinogen assays has taken on new importance as a consequence of this potential role as an atherosclerotic risk factor. This article reviews the performance characteristics of 40,000 fibrinogen assays comprising the College of American Pathologists Proficiency Testing Program from 1988 through 1991. Instrument and reagent variables both play roles in the poor interlaboratory reproducibility documented by this study. The absence of either a national or international standard for plasma fibrinogen assays has been a major source of reagent variability. The validation and calibration of the College of American Pathologists lyophilized plasma reference preparation for fibrinogen determination is also reported in this study. The availability of this validated reference plasma should markedly improve interlaboratory reproducibility.