Evaluation of two microhematocrit methods for quantitating plasma fibrinogen.

Blood samples from several animal species, including man, were used to compare 2 heat-precipitation assays (Millar et al and Schalm et al) with a reference assay (Ratnoff-Menzie) for quantitating plasma fibrinogen. Compared with the Ratnoff-Menzie assay, the heat-precipitation methods significantly underestimated plasma fibrinogen content. The reproducibility of the Millar et al assay was significantly better than that of the Schalm et al assay and approached that of the Ratnoff-Menzie method. The Millar et al assay, a practical test not requiring specialized equipment, is recommended for clinical use in animals.