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Molecular Testing in Bacterial Vaginosis: Separating Technological Hype from Sound Medical Practice

By Kathy Murphy, Ph.D and Yan Lemeshev, M.D.


Bacterial vaginosis (BV) is a clinical condition resulting from a shift in vaginal flora from the normal hydrogen peroxide producing Lactobacillus Sp. to an anaerobic gram negative and variable group of bacteria. Patients with BV are most commonly asymptomatic; however, when symptomatic, complaints can include a whitish vaginal discharge and an unpleasant (fishy) odor. More significantly, BV has been implicated in a wide range of gynecological conditions including increased susceptibility to certain sexually transmitted infections (HIV, N. gonorrhoeae, C. trachomatis, and HSV-2), pre-term delivery, chronic
endometritis, post-hysterectomy vaginal cuff cellulitis, and other infections.

Diagnosis of BV is typically performed by clinical examination, use of Amsel criteria (when microscopy is available) and Gram stain.

A Gram stain using the Nugent’s scoring system is considered the gold standard for laboratory diagnosis, and provides a semi-quantitative evaluation of the relative concentrations of Gram-positive rods (Lactobacillus Sp.), Gram-negative and variable rods and cocci (G. vaginalis, Prevotella sp., Porphyromonas sp., and peptostreptococci), and curved Gram-negative rods (i.e., Mobiluncus sp.). While Gram stain can provide good sensitivity and reasonable specificity, this test takes more time, resources and technical expertise than comparable automated molecular tests.


Unfortunately, with the proliferation of advanced molecular testing platforms, some laboratories have gone far beyond the guidance given by the CDC, ACOG and the WHO. They offer vast and complex arrays of molecular tests for the diagnosis of BV. Their dizzying test menus offer the ability to detect numerous specific bacteria thought to be associated with BV.


But, simply identifying the presence of an organism does not indicate that it is the causative agent in a patient suspected to have BV. Also, which tests would be appropriate and cost-effective to make the diagnosis of BV? Does insurance even pay for those tests, or does the patient get stuck with a huge bill for a large panel of tests?

ProPath understands clinicians need a partner to help them distill pertinent literature into actionable testing panels. We develop and, as warranted, expand our test menu driven by sound, literature-based evidence in order to provide you with the best, most cost-effective and quickest diagnoses.

Our Basic Vaginitis Panel offers molecular testing of the 3 most common causes of vaginitis – Garderella vaginalis, Candida sp. and Trichomonas vaginalis (TV). These molecular tests are highly sensitive and specific in organism identification. In fact, our TV test, using the FDA-approved Hologic APTIMA® Trichomonas vaginalis Assay, has a sensitivity and specificity of over 99%. This panel is currently offered with 24-hour turnaround time to allow you to initiate treatment as soon as possible for your patients. In addition, we have the capability to reflex to Candida speciation, our Expanded BV Panel, and CT/NG.
We believe this is the most cost-efficient and quickest panel of tests available anywhere.

Our Expanded BV Panel is for evaluation of patients with resistant or recurrent bacterial vaginosis. We test for high yield organisms most-likely to be found in these cases and perform quantitative evaluation of Lactobacillus species in addition to the pathogenic organisms Gardnerella vaginalis, Atopobium vaginae, Megaspheara phylotype 1, and BVAB2. When compared to Amsel criteria our panel organisms show sensitivities and specificities, as follows:

The combination of evaluating healthy Lactobacillus sp. and pathogenic organisms in a quantitative fashion allows for a more complete picture of the process occurring in the vaginal microbiome and a more accurate diagnosis of BV. Our testing algorithm stands in contrast to laboratories that offer simple identification of a large and expensive list of organisms that may or may not be causing the patient’s symptoms or those that offer panels including low-yield organisms less likely to be a causative agent of BV.

3. J Clin Microbiol. 1992; 30(3):642.
4. Fredricks DN, Fiedler TL, Thomas KK, Oakley BB, Marrazzo JM. 2007. Targeted PCR for detection of vaginal bacteria associated with bacterial vaginosis. J Clin Microbiol 45:3270-3276.


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