What is the purpose of a Bacterial Vaginosis (BV) test?

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From the Guidelines

All symptomatic pregnant women should be tested and treated for BV to reduce the risk of premature rupture of the membranes, preterm labor, preterm birth, and post-partum endometritis. The diagnosis of BV can be made using clinical or Gram-stain criteria, which include a homogeneous, white, noninflammatory discharge, the presence of clue cells, a pH of vaginal fluid >4.5, and a fishy odor of vaginal discharge before or after addition of 10% KOH (i.e., the whiff test) 1.

Key Points to Consider

  • The benefits of therapy for BV in pregnant women are to relieve vaginal symptoms and signs of infection, reduce the risk for infectious complications associated with BV during pregnancy, and reduce the risk for other infections 1.
  • Oral metronidazole or clindamycin are the recommended options for treatment, and a follow-up evaluation should be done one month after completion of treatment to verify that therapy was effective 1.
  • BV is associated with having multiple sex partners, douching, and lack of vaginal lactobacilli, and it is unclear whether BV results from acquisition of a sexually transmitted pathogen 1.
  • Treatment of the male sex partner has not been beneficial in preventing the recurrence of BV, and partners typically do not need treatment as BV is not considered a sexually transmitted infection 1.

Recommendations for Treatment

  • Metronidazole (500mg orally twice daily for 7 days or 0.75% gel intravaginally once daily for 5 days) or clindamycin (300mg orally twice daily for 7 days or 2% cream intravaginally at bedtime for 7 days) are commonly used to treat BV.
  • It is essential to complete the full course of antibiotics even if symptoms improve before finishing treatment.
  • Avoiding douching, using condoms, and limiting sexual partners may help prevent recurrence.

From the Research

Bv Test

  • The diagnosis of bacterial vaginosis (BV) is typically made using a combination of symptoms, physical examination findings, and office-based or laboratory testing 2.
  • The Amsel criteria are commonly used to diagnose BV, which include vaginal pH greater than 4.5, positive whiff test, milky discharge, and the presence of clue cells on microscopic examination of vaginal fluid 3.
  • Gram stain is considered the diagnostic standard for BV, but newer laboratory tests that detect Gardnerella vaginalis DNA or vaginal fluid sialidase activity have similar sensitivity and specificity to Gram stain 2.
  • Treatment options for BV include oral metronidazole, intravaginal metronidazole, or intravaginal clindamycin, with cure rates ranging from 75% to 86% 4.
  • It's worth noting that the study from 1979 5 is not relevant to the diagnosis or treatment of BV, as it discusses a rapid technique for measuring calcium uptake in mitogen-induced T and B lymphocytes.

Diagnosis and Treatment

  • The diagnosis of vulvovaginal candidiasis is made using a combination of clinical signs and symptoms with potassium hydroxide microscopy, and DNA probe testing is also available 2.
  • Culture can be helpful for the diagnosis of complicated vulvovaginal candidiasis by identifying non-albicans strains of Candida 2.
  • Treatment of vulvovaginal candidiasis involves oral fluconazole or topical azoles, although only topical azoles are recommended during pregnancy 2.
  • Trichomoniasis is diagnosed using nucleic acid amplification testing, and treatment involves oral metronidazole or tinidazole, with patients' sex partners also being treated 2.

Noninfectious Vaginitis

  • Noninfectious causes of vaginitis, including atrophic, irritant, allergic, and inflammatory vaginitis, are less common and account for 5% to 10% of vaginitis cases 2.
  • Atrophic vaginitis is treated with hormonal and nonhormonal therapies, while inflammatory vaginitis may improve with topical clindamycin and steroid application 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Vaginitis: Diagnosis and Treatment.

American family physician, 2018

Research

Vaginitis.

American family physician, 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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