Rheumatic Disease:

March 01, 2004 ABSTRACT: The basic screening studies for rheumatic diseases are a complete blood cell count, a determination of the erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) level, a rheumatoid factor assay, an antinuclear antibody (ANA) test, a measurement of serum uric acid level, and a urinalysis. Test results must be interpreted within a clinical context; for example, a positive ANA assay suggests the possibility of a rheumatic disorder, but it is not specific for any diagnosis. Tests that reveal the nature and extent of target-organ involvement, such as renal function studies in patients with systemic lupus erythematosus, can help guide the selection of therapy. Laboratory results also reflect disease activity; the ESR and CRP level are useful gauges of the activity of most inflammatory rheumatic disorders. Finally, laboratory monitoring can help you minimize the significant toxicity associated with many of the drugs used to manage rheumatic diseases.