Laboratory testing in the rheumatic diseases: a practical review.

Laboratory testing for the rheumatic diseases can allow for rapid diagnosis and appropriate management, while false-positive tests can lead to inappropriate management and unnecessary concern for the patient. An evaluation of laboratory testing for rheumatic illnesses is discussed, including the well-known acute phase proteins, the use of ANA in screening, and the newer antibodies which may potentially allow for an earlier diagnosis. A thorough history and examination are arguably the best screening tests. Clinicians should be judicious in their use of laboratory testing, and should only do so in an attempt to further refine the diagnosis.