[Blood sedimentation--a simple and useful test?]

Abstract

The erythrocyte sedimentation rate is one of the most frequently used laboratory tests in clinical medicine. The sedimentation rate is determined by the aggregation of erythrocytes, in which plasmatic and erythrocytic factors are involved. Plasmatic factors include high-molecular proteins such as fibrinogen, globulins (immunoglobulins, especially IgM, alpha 2-globulins) and immune complexes (e.g. cryoglobulins). Albumin, a smaller protein with a spherical structure, decreases erythrocyte aggregation. Erythrocytic factors play an equally important role. Anemia and macrocytosis lead to an increase in sedimentation rate, whereas the presence of abnormal red cell shapes and deformability decrease the sedimentation rate. The diversity of factors involved often renders the interpretation of sedimentation rates difficult. Normal values for females are higher than for males and increase with age. The sedimentation rate is not useful for screening of asymptomatic subjects, e.g. the detection or exclusion of a malignant tumor. It is appropriate in monitoring the course of diseases such as arteritis temporalis or polymyalgia rheumatica. The sedimentation rate should therefore be used in a more restrictive and selective manner.