C-reactive protein in the evaluation of antibiotic therapy for pelvic infection.

C-reactive protein (CRP), an acute-phase reactant not found in normal serum, has previously been shown, by qualitative assay, to differentiate inflammatory from noninflammatory pelvic pathology. In this study, quantitative measures of serum CRP were obtained concomitantly with white blood counts (WBC) and erythrocyte sedimentation rates (ESR) in patients being treated for pelvic infection. CRP levels and their changes, which were not known to physicians treating the patients, accurately indicated those patients who would need supplementary antibiotics to achieve remission. WBC levels were misleading in over half the patients, and the ESR bore no relationship to the clinical situation. The data suggest that CRP may be used to assess the efficacy of antibiotic therapy in pelvic infection. Our successful use of single-agent therapy in most cases also suggests that the use of multiple antibiotics is unnecessary and that CRP levels can indicate when additional antibiotics are appropriate.