Autoantibody testing: procedures and significance in systemic rheumatic diseases.

The detection of ANA and the determination of their precise biochemical specificity is an important adjunct to the investigation of patients that have systemic rheumatic disease. Some of these antibodies have clearcut diagnostic and prognostic significance giving the informed clinician important information in the management of diseases with protean manifestations. The performance of the ANA test should be undertaken with a clear understanding of the importance of the substrate being used and the interpretation of certain patterns of staining. For most nuclear antigens (DNA, nRNP, Sm, etc.) cropreserved organ sections are adequate. However, antibodies directed to other antigens (PCNA, centromere, etc.) are best detected on tissue culture cell substrates. The availability of reference sera [99] has become an important advancement in the standarization of these tests. In spite of a large body of literature relating to the biochemistry and clinical significance of these antibodies much more needs to be done to complete our understanding of the role of these antibodies in the pathogenesis of disease.