Efficiency of haematological screening tests for detecting disease.

A new "intermediate' reference (normal) range for the erythrocyte sedimentation rate has been compared with published "low' and "high' reference ranges in a study of 354 hospital patients. The "intermediate' range showed superior balance between sensitivity and specificity in the detection of disease-induced plasma protein abnormalities and and gave a test efficiency of 81.9%; this reference range can therefore be recommended for routine use in the diagnostic laboratory. Four other screening tests (whole-blood viscosity, plasma viscosity, zeta sedimentation ratio, and C-reactive protein level) were compared in the same 354 patients. Whole-blood viscosity proved to be unsuitable as a screening test (efficiency 44.8%) but the three other tests showed good balance between sensitivity and specificity and gave a test efficiency of 74.4-79.7%.