Micromethod for the Estimation of Plasma Fibrinogen.

Fibrinogen is quantitatively precipitated from plasma by 1.20 M phosphate buffer. The amount of precipitated fibrinogen is determined turbidimetrically at 450 m5. The method requires 0.25 ml. of plasma for the blank and sample. Reliability of the method has been established by comparison with an ammonium sulfate turbidimetric method and a colorimetric method, demonstration of specificity, variation in incubation temperature, demonstration of optimal molarity and pH, and replicate analyses.