Re-evaluation of heat precipitation method for plasma fibrinogen estimation: effect of abnormal proteins and plasma viscosity.

The heat precipitation method (Aberdeen method) was compared with the Ratnoff and Menzie method of fibrinogen assay in 320 donors, including normals and patients suffering from malignant melanoma, renal failure, hypertension, multiple myeloma, etc. Excellent correlation (r=0-8287, p less than 0-000 000 1) was found between these two methods. However, on some occasions individual low results were obtained by the Aberdeen method in the presence of cryoglobulins or excessively high plasma viscosity. The latter effect was tested also by additions of albumin, glucose, and dextrans.