By Kathleen M. Murphy, Ph.D.
Background: Vaginitis is one of the most common problems in clinical medicine, accounting for > 10 million office visits each year. Vaginal symptoms such as discharge, odor, burning, and inflammation can be caused by a number of microbial agents including bacteria, yeast and protozoa. The FDA-approved BD Affirm VPIII test identifies three of the most common causes of vaginitis: Gardnerella vaginalis, Candida species, and Trichomonas vaginalis.
Bacterial vaginosis (BV): BV is the most common vaginal infection. In addition to causing discomfort, BV infections increase risk of late miscarriage, and preterm labor and delivery. Despite extensive study, the cause of BV remains controversial. In general, Gardnerella vaginalis is thought to be essential, or at least a major contributing factor, for the development of BV. However, the development of BV may also require the overgrowth of additional bacteria, including Mycoplasma, Peptostreptococcus, Mobiluncus or Bacteroides species. As many women harbor low numbers of these potentially pathogenic bacteria without a reduction in the normal vaginal flora, and without symptoms of BV, the clinical utility of detecting low numbers of these agents by sensitive methods such as PCR amplification is currently unproven. This test uses a direct detection method (not PCR amplification) to detect Gardnerella vaginalis.
Candida species: Yeast infections are the second most common form of vaginal infection. Seventy-five percent of all adult women will experience at least one episode of vaginal candidiasis during their lifetime Yeast infections are almost exclusively caused by members of the Candida genus.
Trichomonas vaginalis: Trichomonas is a sexually-transmitted protozoan parasite. In the US, approximately 3 million women will contract Trichomonas vaginalis each year. Pregnant women with T. vaginalis infection have an increased risk of pre-term labor and delivery.
Assay: The FDA-approved BD Affirm VPIII test is a nucleic acid hybridization assay that uses 2 unique nucleic acid probes specific for each detected organism. This test provides an objective approach to the diagnosis of vaginitis. The test characteristics are shown in the table below.
ProPath offers the BD Affirm VPIII test. Turnaround time is 24 hours from time received in our laboratory. Contact yourservice representative for more information.
1. BD Affirm VPIII product insert 2009/01
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