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Bacterial Vaginosis/Vaginitis Panel

Bacterial Vaginosis/Vaginitis Panel

Test Highlight

Bacterial Vaginosis/Vaginitis Panel


Clinical Use

  • Differential diagnosis of vaginosis/vaginitis in symptomatic women

  • Guide selection of appropriate therapy

Clinical Background

Vaginal symptoms such as abnormal discharge, unpleasant odor, itching, and burning are common reasons for gynecologic consultation and typically lead to a diagnosis of bacterial vaginosis (BV), parasitic vaginitis (vaginal trichomoniasis; VT), or yeast vaginitis (vaginal candidiasis; VC).

BV is the most common finding in women with vaginal symptoms, affecting 22% to 50% of symptomatic women.1 Although not sexually transmitted, it can occur as a coinfection with a sexually transmitted infection (STI). BV is characterized by replacement of normal Lactobacillus flora with anaerobic and other bacteria. For example, an abnormally high level of Gardnerella vaginalis, a part of the normal flora, is a marker of BV. Treatment of BV for symptomatic women is recommended to relieve symptoms and potentially reduce the risk of acquiring other STIs.2

VT is an STI caused by Trichomonas vaginalis and it is estimated that 5 million women are infected each year in the United States.3 VT is diagnosed in 4% to 35% of women presenting with symptoms of vaginosis/vaginitis.1 VT has been associated with increased risk of acquiring human immunodeficiency virus (HIV).

BV and VT are both associated with adverse pregnancy outcomes, including premature rupture of the membranes, preterm labor and delivery, and low birth weight. The CDC thus recommends evaluation and treatment of BV and VT for symptomatic pregnant women.2 The benefits of BV treatment for asymptomatic pregnant women are unclear. Screening is not recommended for asymptomatic women with a low risk of preterm delivery,4 and there is not enough evidence to recommend screening in women with high risk.2,4 For asymptomatic VT, pregnant women should be counseled about risks of therapy and be given the option of postponing treatment until 37 weeks’ gestation or later. However, routine screening is not recommended.2

VC is present in 17% to 39% of symptomatic women.1 About 75% of women develop VC at some point during their lifetime and approximately 45% will suffer a second occurrence; 5% have recurrent candidiasis, which is frequently intractable.2 Although C albicans accounts for 80% to 90% of such infections, VC has also been associated with C glabrata, C parapsilosis, and C tropicalis and, rarely, with C kefir, C krusei, C pseudotropicalis, C lusitaniae, and C rugosa.5

Identifying the cause of vaginosis/vaginitis is essential for selection of pathogen-specific therapy. Clinicians have traditionally diagnosed vaginal infection using a combination of gynecologic examination, vaginal pH, microscopic evaluation of Gram stain and/or wet mount, and an amine odor test. Such procedures fail to support a diagnosis in approximately 30% of symptomatic patients and cannot detect mixed infections, which are common. Nucleic acid probe testing, which is more sensitive and specific than the office procedures mentioned above,6 avoids these limitations.


In this nucleic acid probe assay, specific DNA probes are hybridized to the ribosomal RNA of Candida species, G vaginalis, and T vaginalis. Each organism is detected with separate capture and color development probes. The analytical sensitivity is 1 x 104 CFU/assay for Candida species, 2 x 105 CFU/assay for G vaginalis, and 5 x 103 trichomonads/assay for T vaginalis. Results are reported as detected or not detected for each organism.

The Candida species detected include C albicans, C glabrata, C kefir, C krusei, C parapsilosis, and C tropicalis.

Interpretive Information

The sensitivity and specificity of this nucleic acid probe assay, relative to 2 reference methods (microscopy and culture), are listed in the Table. For cases in which probe results were positive and the reference method result was negative (ie, potential false-positive), alternative methods were used to reconcile the discrepancy.

Table. Clinical Sensitivity and Specificity of the Nucleic Acid Probe Assay Relative to
2 Reference Methods7


Size, N

Nucleic Acid Probe Assay

Relative to Microscopy

Relative to Culture
Sensitivity (%) Specificity (%) Sensitivity (%) Specificity (%)
Candida species 740



G vaginalis 299





T vaginalis 852





a Culture is the accepted reference method.
b Based on Gram stain, the accepted reference method.
c Based on wet mount.

In symptomatic patients, a “detected” result for Candida species and T vaginalis is diagnostic of VC and VT, respectively. Because G vaginalis is normally found in the vagina, a “detected” result, although suggestive, is not definitive proof of BV. Results should be interpreted in conjunction with other test results and clinical findings. Adjunct tests useful to support a diagnosis of BV include vaginal pH (>4.5 in 90% of BV), the presence of clue cells (ie, epithelial cells with adherent coccobacilli) in a vaginal discharge wet mount, and a positive amine odor test.

A “not detected” result suggests that the patient is not infected with the target organism(s), but could also be due to an organism concentration below the assay detection limit or to improper specimen collection and handling.

Test performance has not been evaluated in patients treated with antimicrobial therapy; therefore, the test should not be used to monitor treatment.


  1. ACOG Practice Bulletin: Vaginitis. Obstet Gynecol. 2006;107:1195-1206.

  2. Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2010. MMWR Recomm Rep. 2010;59(RR-12).

  3. American Social Health Association. Sexually transmitted diseases in America: How many cases and at what cost? Available at: http://www.kff.org/womenshealth/1445-std_rep.cfm. Accessed May 17, 2006.

  4. U.S. Preventive Services Task Force. Screening for bacterial vaginosis in pregnancy to prevent preterm delivery: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2008;148:214-219.

  5. Rein MF. Vulvovaginitis and cervicitis. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. New York, NY: Churchill Livingstone; 2000:1218-1235.

  6. Brown HL, Fuller DD, Jasper LT, et al. Clinical evaluation of Affirm VPIII in the detection and identification of Trichomonas vaginalis, Gardnerella vaginalis, and Candida species in vaginitis/vaginosis. Infect Dis Obstet Gynecol. 2004;12:17-21.

  7. BD Affirm™ VPIII Microbial Identification Test. http://www.bd.com/ds/technicalCenter/inserts/pkgInserts.asp#PF8. Accessed June 16, 2010.

Content reviewed 07/2013

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