From the Guidelines
A wet mount preparation is indicated for diagnosing vaginal infections, particularly Trichomonas vaginalis, and should be performed when a patient presents with symptoms such as abnormal vaginal discharge, itching, burning, or odor, as it allows for the detection of motile trichomonads 1. The indications for a wet mount preparation include:
- Suspected trichomoniasis
- Suspected vulvovaginal candidiasis
- Evaluation of unexplained vaginal discharge To perform a wet prep:
- Collect a sample of vaginal discharge using a cotton swab
- Place the sample on a glass slide
- Add a drop of saline solution
- Cover with a coverslip and examine under a microscope Look for:
- Motile trichomonads (trichomoniasis)
- Yeast cells or pseudohyphae (candidiasis) The wet prep is a useful diagnostic tool, especially in resource-limited settings, as it is quick, inexpensive, and readily available, allowing for prompt diagnosis and treatment of common vaginal infections, although its sensitivity and specificity may vary widely, ranging from 40% to 70% for both Trichomonas vaginalis and vulvovaginal candidiasis 1. The presence of motile trichomonads on a wet mount preparation is diagnostic of trichomoniasis, and proficiency in microscopic examination is essential for accurate diagnosis 1.
From the Research
Indications for a Wet Mount Preparation
The indications for a wet mount (microscopic) preparation include:
- Diagnosis of bacterial vaginosis, which is characterized by the presence of clue cells in the wet mount preparation 2, 3, 4
- Diagnosis of trichomoniasis, although the sensitivity of wet mount preparation for this condition is low 2, 3, 5, 4
- Diagnosis of vulvovaginal candidiasis, which can be diagnosed using a combination of clinical signs and symptoms with potassium hydroxide microscopy, although wet mount preparation is not the primary method of diagnosis 2, 3, 4, 6
- Evaluation of vaginal discharge and identification of other vaginal pathogens 5, 6
Characteristics of Vaginitis Diagnosed using Wet Mount Preparation
The characteristics of vaginitis diagnosed using wet mount preparation include:
- Bacterial vaginosis: presence of clue cells, milky discharge, pH greater than 4.5, and positive whiff test 2, 3, 4
- Trichomoniasis: presence of Trichomonas vaginalis, foul-smelling, frothy discharge, and vaginal inflammatory changes 2, 3, 5, 4
- Vulvovaginal candidiasis: presence of yeast, thick, white discharge, dysuria, vulvovaginal pruritus, and swelling 2, 3, 4, 6
Limitations of Wet Mount Preparation
The limitations of wet mount preparation include: