From the Guidelines
Testing for bacterial vaginosis (BV) and trichomoniasis (trich) typically involves clinical evaluation and laboratory tests, with nucleic acid amplification tests (NAATs) being the most sensitive method for both conditions. For BV, healthcare providers use Amsel's criteria (checking for vaginal discharge, fishy odor, vaginal pH above 4.5, and clue cells under microscope) or Nugent scoring of a Gram stain 1. A simple in-office test involves mixing vaginal discharge with potassium hydroxide to detect the characteristic fishy odor (whiff test). For trichomoniasis, providers may perform a wet mount microscopy to look for motile trichomonads, use rapid antigen tests, or order NAATs from vaginal, cervical, or urine samples.
Some key diagnostic tests for BV and trichomoniasis include:
- Amsel's criteria for BV
- Nugent scoring of a Gram stain for BV
- Wet mount microscopy for trichomoniasis
- Rapid antigen tests for trichomoniasis
- NAATs for both conditions
It's essential to note that self-testing kits are available for home use, though they're less accurate than clinical tests 1. If symptoms like unusual discharge, odor, itching, or pain occur, it's crucial to seek medical evaluation promptly as both conditions require prescription treatment and can lead to complications if left untreated. The most recent and highest quality study recommends using NAATs for diagnosis, as they offer the highest sensitivity for both BV and trichomoniasis 1.
In terms of laboratory tests, the following specimens can be used:
- Vaginal discharge for wet mount microscopy and NAATs
- Cervical or urine samples for NAATs
- Swab of vaginal discharge for culture or DNA hybridization probe
Overall, NAATs are the most sensitive method for diagnosing BV and trichomoniasis, and should be used as the primary diagnostic test 1.
From the Research
Diagnostic Tests for Bacterial Vaginosis (BV)
- The diagnosis of BV is commonly made using the Amsel criteria, 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 2, 3.
- Gram stain is the diagnostic standard for BV, and newer laboratory tests that detect Gardnerella vaginalis DNA or vaginal fluid sialidase activity have similar sensitivity and specificity to Gram stain 4.
- The BVBlue test is a point-of-care test that has been evaluated for the diagnosis of BV, and it performed well compared with conventional diagnostic methods, with a sensitivity of 88% and a specificity of 95% 5.
- Nugent's Gram stain scale is also a commonly used diagnostic method for BV 6.
Diagnostic Tests for Trichomoniasis (Trich)
- The diagnosis of trichomoniasis is made using a combination of symptoms, physical examination findings, and office-based or laboratory testing 4.
- Microscopy is more reliable for diagnosing trichomoniasis, and features of trichomoniasis include trichomonads seen microscopically in saline, more leukocytes than epithelial cells, positive whiff test, and vaginal pH greater than 5.4 2.
- Culture and DNA probe testing are useful in diagnosing trichomoniasis, and examinations of wet-mount preparations have a high false-negative rate 3.
- The Centers for Disease Control and Prevention recommends nucleic acid amplification testing for the diagnosis of trichomoniasis in symptomatic or high-risk women 4.