Laboratory evaluation in rheumatic diseases

Autoantibodies can help clinicians to allow early detection of autoimmune diseases and their clinical manifestations, to determine effective monitoring of prognosis and the treatment response. From this point, they have a high impact in rheumatic disease management. When used carefully they allow rapid diagnosis and appropriate treatment. However, as they may be present in healthy population they may cause confusion for interpreting the situation. False positive test results may lead to wrong treatment and unnecessary anxiety for patients. Autoantibody positivity alone does not make a diagnosis. Similarly, the absence of autoantibodies alone does not exclude diagnosis. The success of the test is closely related to sensitivity, specificity and likelihood ratios. So, interpretation of these is very important for a proper laboratory evaluation. In conclusion, in spite of the remarkable advances in science and technology, a deeply investigated anamnesis and comprehensive physical examination still continue to be the best diagnostic method. The most correct approach is that clinicians apply laboratory tests to confirm or exclude preliminary diagnosis based on anamnesis and physical examination. This review will discuss these issues.