Seropositivity of the rapid plasma reagin (RPR) test in a dental school patient population: a retrospective study.

Objectives: The purpose of this retrospective study was to determine the seropositivity of the rapid plasma reagin (RPR) in a dental school patient population. Methods: Blood was drawn on 20,844 subjects registering for treatment at the Louisiana State University School of Dentistry. All subjects who are admitted to the dental school are submitted to RPR screening (Macro-Vue-RPR Card, Becton Dickinson), blood indices, and serum chemistries. Venereal Disease Research Laboratory (VDRL), microhemagglutination assay for Treponema pallidum (MHA-TP) and/or fluorescent treponemal absorption test for Treponema pallidum (FTA-ABS) were also run on the positive RPR results. Results: Two hundred seventy-nine (1.34%) of the 20,844 were RPR-positive. Sixty-two subjects (0.30%) of this total population from the RPR-positive findings were nonreactive (biological false positives or BFP) to the MHA-TP and FTA-ABS. This left 217(1.04%) subjects of the 20,844 screened who were seropositive on both the RPR and the FTA-ABS or MHA-TP. Conclusions: Since this study has not been performed in a dental school patient population setting, comparison with other institutions is difficult. The authors agree that routine RPR testing is helpful and cost effective to detect patients possibly infected with Treponema pallidum in a large patient population.