A comparison of the plasma viscosity and the erythrocyte sedimentation rate as screening tests.

Plasma viscosity (PV) and the erythrocyte sedimentation rate (ESR) were determined in 343 patients. The results were correlated with the presence or absence of a clinical diagnosis usually associated with a raised ESR. The percentages of false-positive results were 4,9% and 3,8% and those of false-negative results were 12,8% and 13,1% for the PV and ESR respectively. PV measurements led to the detection of 8 cases of hypoproteinaemia in patients with normal ESR values, and could also detect and quantify hyperproteinaemias. In coeliac disease the PV correlated closely with the total plasma protein measurement. In a case of subacute bacterial endocarditis (SBE) the two tests varied with the disease process in approximately parallel fashions. PV measurements have several important technical advantages over the ESR, and could replace the ESR as a primary screening test for organic disease. They can also be used to detect hypoproteinaemia in a malnourished population.