Laboratory tests in the rheumatic disease.

Because the pathophysiologic relationship between laboratory and clinical abnormalities in many of the rheumatologic diseases is still not clearly understood, the use of the investigations dealt with in this article is based only upon statistics. The interpretation of these tests is therefore highly dependent on the result of the initial clinical assessment. Having accepted this limitation, however, the rheumatologist has available a number of powerful tools which may be used to diagnose, classify, or prognosticate.