Evaluation of components of gingival crevicular fluid as diagnostic tests

Gingival crevicular fluid (GCF) is an inflammatory exudate that can be collected at the gingival margin or within the gingival crevice. The biochemical analysis of the fluid offers a noninvasive means of assessing the host response in periodontal disease. In recent years, the relationship of measures of the inflammatory response in GCF to risk for development of active periodontal disease (defined as clinical attachment loss or radiographic bone loss) has been studied in longitudinal trials. The greatest interest has focused on prostaglandin E2, an arachidonic acid metabolite; beta-glucuronidase and neutrophil elastase, markers of lysosomal enzyme release from neutrophils; and aspartate aminotransferase, a cytoplasmic enzyme indicative of cellular necrosis. Analysis of the data allows a number of conclusions to be drawn concerning the potential diagnostic significance of GCF: 1) an exuberant host inflammatory response is associated with progressive disease in patients with periodontitis; 2) collection of GCF using small precut strips is a reproducible and reliable collection technique; 3) the total amount of the mediator and not concentration of the mediator in the GCF sample can be reported when timed samples are collected; and 4) technology exists for GCF-based diagnostic tests to be performed in the dental office. Nevertheless, many questions remain. Still to be determined are: 1) the relationship of test results to the development of periodontitis in patients with gingivitis; 2) the level of test accuracy needed to justify use of these tests; 3) the unit of observation (patient, site) that is being evaluated by the test; and 4) the need for such tests as perceived by clinicians. While these questions are formidable, introduction of GCF-based diagnostic tests will provide clinicians with an improved, quantitative means of evaluating patients and offer specific criteria to assess the effectiveness of treatment.