Use of a lactoferrin assay in the differential diagnosis of female genital tract infections and implications for the pathophysiology of bacterial vaginosis.

BACKGROUND AND OBJECTIVES: Lactoferrin has served as a marker for leukocytes (polymorphonuclear neutrophils [PMN]) in clinical specimens. GOAL: To investigate the potential of a lactoferrin latex agglutination test in the differential diagnosis of female genital infection. STUDY DESIGN: Lactoferrin was quantified in the vaginal discharge of women with genital infections. Polymorphonuclear neutrophils were added to vaginal discharge and observed over 8 hours. RESULTS: Vaginal lactoferrin titers were significantly elevated in women with trichomoniasis, candidiasis, and bacterial vaginosis (BV). Using a lactoferrin titer of > or = 1:40, the assay has a sensitivity of 79.3% and a specificity of 83.3% for the presence of trichomoniasis or bacterial vaginosis. Vaginal discharge from women with BV significantly destroyed added PMN. CONCLUSIONS: Vaginal lactoferrin determinations may provide a useful screen for inflammatory genital infections and identify individuals who require additional diagnostic evaluation. The observed absence of PMN in bacterial vaginosis may result from the destruction of PMN in vaginal discharge rather than the absence of a primary inflammatory response.