A vaginal wet mount (or vaginal smear or wet prep) is a gynecologic test wherein a sample of vaginal discharge is observed by wet mount microscopy by placing the specimen on a glass slide and mixing with a salt solution. It is used to find the cause of vaginitis and vulvitis.
Vaginal wet mounts are used in case of vaginitis symptoms such as vaginal itching, burning, rash, odor, or discharge. It may assist in suspicion of vaginal yeast infection, trichomoniasis and bacterial vaginosis.
Infections such as chlamydia, genital warts, syphilis, herpes simplex, and gonorrhea can also affect the vagina, but these diseases are found by doing other tests.
It may also be used in a rape investigation to detect presence of semen.
Vaginal wet mounts are not done during the menstrual period, because menstrual blood on the slide can confound the results. Vaginal irrigation, tampon use or sex (potentially disrupting the vaginal pH) should be avoided for 24 hours before the test. Vaginal medicines (such as a nonprescription vaginal yeast medicine) should not be used during the 2 to 3 days before the test.
The sampling is done with the patient in lithotomy position. A speculum is used to facilitate use of a swab or spatula to sample fluid inside the vagina. The sampling procedure may cause some discomfort and minor bleeding, but otherwise there are no associated risks. The sample is then smeared upon a microscope slide and is observed by wet mount microscopy by placing the specimen on a glass slide and mixing with a salt solution.