Variability in fibrinogen measurements: an obstacle to cardiovascular riskstratification

The clinical utility of fibrinogen measurement has been limited by large in traindividual variability. Several approaches that have been shown to impro ve the repeatability of fibrinogen include acquisition of samples at the sa me time of day, standardized sample procurement techniques, and multiple re plicate sampling. This study employed established pre-analytical and analyt ical techniques known to reduce fibrinogen variability, including the acqui sition of three replicate samples, each analyzed in duplicate, to evaluate the impact of intraindividual variability in fibrinogen measurement at base line and 3 months on cardiovascular risk in 60 healthy subjects. Classifica tion accuracy was evaluated by the ability to categorize subjects into tert iles of fibrinogen. Only 55% (33/60) of the subjects were correctly assigne d to the appropriate fibrinogen tertile. Fibrinogen measurements varied by more than 10% in 45% of subjects and by 5% in 80% of subjects. Intraindivid ual variability in fibrinogen measurement with a functional assay limits ca rdiovascular risk assessment even when three replicates are averaged. (C) 2 001 Elsevier Science Ireland Ltd. All rights reserved.