ANA testing: a comparison of two kits and a discussion of specificity and sensitivity as criteria for selection of screening procedures.

A comparative evaluation of two commercial kits that detect antinuclear antibodies via indirect immunofluorescence was undertaken using an adult ambulatory population. The sensitivity and specificity of the kits were compared to determine which of the two was more efficient as a screening test for systemic lupus erythematosus specifically and connective tissue disease in general. Both were equally efficient. The authors emphasize the importance of accurate clinical information in verifying health/disease status when attempting to compare the efficacy of laboratory tests, especially screening procedures. Also important is a valid assessment of the number of false positives likely to be present in the test population, and this is best determined through prospective evaluation.