From the Guidelines
Testing for vulvovaginitis should involve a combination of physical examination, microscopic evaluation of vaginal discharge, and nucleic acid amplification tests (NAATs) to identify the underlying cause, as recommended by the most recent and highest quality study 1. The primary diagnostic approach includes a thorough physical examination with a pelvic exam, followed by microscopic evaluation of vaginal discharge using wet mount preparation, potassium hydroxide (KOH) preparation, and pH testing.
- Vaginal cultures may be collected to identify bacterial pathogens, particularly for bacterial vaginosis.
- NAATs are highly sensitive for detecting sexually transmitted infections like chlamydia, gonorrhea, and trichomoniasis.
- Point-of-care tests such as the whiff test (adding KOH to discharge to detect amine odor) can help diagnose bacterial vaginosis.
- DNA probe tests can identify Candida, Gardnerella, and Trichomonas. For recurrent or persistent cases, additional testing may include:
- Glucose tolerance tests to rule out diabetes.
- HIV testing if immunosuppression is suspected.
- Vulvar or vaginal biopsies to exclude other conditions. These diagnostic methods help clinicians determine the specific cause of vulvovaginitis, which is essential for selecting appropriate treatment, as different pathogens require different therapeutic approaches, as noted in 1. It's worth noting that the sensitivity of wet mount for trichomonads requires live organisms to visualize movement and has poor sensitivity, as mentioned in 1 and 1. However, the most recent study 1 provides the most up-to-date guidance on diagnostic methods for vulvovaginitis.
From the Research
Methods for Testing Vulvovaginitis
The methods for testing vulvovaginitis include:
- Amsel criteria (milky discharge, pH greater than 4.5, positive whiff test, clue cells in a wet-mount preparation) for bacterial vaginosis 2, 3
- Microscopic examination of a sample from the lateral vaginal wall (10 to 20 percent potassium hydroxide preparation) for vulvovaginal candidiasis 2, 3
- Culture and DNA probe testing for trichomoniasis 2, 3
- Gram stain for bacterial vaginosis 3
- Nucleic acid amplification testing (NAAT) for the diagnosis of vulvovaginal candidiasis, bacterial vaginosis, and Trichomonas vaginalis 4
- Office laboratory diagnostic techniques such as saline wet mount, potassium hydroxide (KOH) prep, amine "sniff", pH, and nucleic acid hybridization test 5
- Physical examination, including speculum and bimanual examinations, to diagnose common causes of vaginitis 6
Diagnostic Tests
The diagnostic tests used to diagnose vulvovaginitis include:
- Wet mount microscopy
- Yeast culture
- Gram stain
- T. vaginalis culture
- NAAT
- DNA probe testing
- Potassium hydroxide (KOH) prep
- Amine "sniff" test
- pH test
Comparison of Diagnostic Tests
The studies compared the sensitivity and specificity of different diagnostic tests, including:
- Microscopy vs. NAAT for diagnosing vulvovaginal candidiasis and Trichomonas vaginalis 4
- Clinician-performed tests vs. DNA hybridization test for diagnosing bacterial vaginosis, Trichomonas vaginalis, and vulvovaginal candidiasis 5
- Examining clinician vs. non-examining clinician for diagnosing bacterial vaginosis, Trichomonas vaginalis, and vulvovaginal candidiasis 6