Vaginal Wet Mount: Introduction, Principle, Preparation, Result Interpretati

Vaginal Wet Mount: Introduction, Principle, Preparation, Result Interpretation, Limitations and Related Videos

Introduction of Vaginal Wet Mount

The vaginal wet mount also called the vaginitis test is very useful for diagnosis vaginal infections that could be causing vaginitis. Vaginitis encompasses a variety of disorders that cause infection or inflammation of the vagina. The causative agents of vaginitis can include bacteria, yeast, viruses, and parasites. Non-infectious vaginitis may also occur due to estrogen imbalance (low level) that causes vaginal dryness as well as a reaction to vaginal products such as soap, bath oils, spermicidal jelly, or douches.

The most common pathogens are as follows-

Bacteria: Gardnarella is a commonly found bacteria in the vagina. Overgrowth results in bacterial vaginosis, Streptococcus or Staphylococcus can also be present but usually do not result in an infection. A bacterial infection can cause a grayish-white discharge with a fishy odor.

Fungi: Candida albicans cause genital itching and a thick, white vaginal discharge with a cottage cheese-like texture.
Viruses: Human papillomavirus (HPV)
Parasites: Trichomonas vaginalis, Pinworms, scabies, and lice can cause inflammation of the vulva and vagina.
Vaginitis is also a sexually transmitted infection (STI).

Symptoms of vaginitis

Common symptoms of vaginitis are as follows-

vaginal discharge that may have an odor
itching or swelling on the outside of the vagina
burning during urination
pain or discomfort during intercourse

Principle of wet mount

Saline wet mount preparation for vaginal smear analyzing a vaginal discharge specimen for diagnosis the causative agents of vaginitis. It utilizes a physiological saline solution (0.85% NaCl ) as an isotonic media to maintain the cellular structure of the various organisms as well as patient cells that are found in vaginal discharge.

Vaginal Wet Mount or Vaginal smear Preparation

A wet mount of vaginal smear also called wet preparation uses to find out the causative agents of vaginal infections that don’t affect the urinary tract. A clinician ( gynecologist) will have you lie down on an exam table with your feet in stirrups, like at a regular gynecologic exam. She/he will insert a speculum into the vagina to help see the area. After that, a sterile cotton swab is inserted into the vagina to obtain a sample of vaginal discharge. The clinician will transfer the sample onto a slide or leaving on the swab. The slide is sent to the microbiology section to check the causative agent of vaginitis.

Requirements for the vaginal wet mount test procedure

Test slides or vaginal discharge on the swab
Physiological saline or normal saline
Microscope
Coverslips
Sterile Wooden Applicator Stick
Gloves

Wet mount procedure

First, wear gloves.
Take a clean and grease-free slide ( no need in case of slides provided by a clinician).
Place s sample of the vaginal discharge on a glass slide.
Add one drop of physiological or normal saline
Mix it properly with a sterile wooden applicator stick and apply a coverslip over a uniform suspension without creating bubbles.
Examine the entire 22- by 22-mm coverslip systematically with the low power objective (10X ) and low light intensity.
If any suspicious objects encounter, examine with the high dry objective (40X).

Observation of Vaginal smear

Look at under a microscope for bacteria, yeast cells, Trichomonas, pus cells ( dead white blood cell), and clue cells that is an indicator of bacterial vaginosis.

Result Interpretation of vaginal smear or vaginal wet mount

Bacteria: The organisms which have a size of this range 0.2 – 2.0 × 1 – 10 µm and shape of normally round or rod.

Trichomonas vaginalis: A moving object usually the size of 10 μm in length and 7 μm in width.

Yeast cells: Oval or round in shape having a size of usually 3-5µm and some with budding

Pus cells: Dead white blood cells form pus and the pus cells having a size of usually 12 to 14 µm with lobes.

Clue cells: Clue cells are epithelial cells of the vagina that get their distinctive stippled appearance by being covered with bacteria.

Uses of wet mount or vaginal smear

It is very useful in vaginal infections to find out –

Bacteria
Yeast cells
Trichomonas
Pus cells and
A clue cell is an indicator of bacterial vaginosis.
vaginal pH determination-The normal vaginal pH is 3.8 to 4.5. Bacterial vaginosis, trichomoniasis, and atrophic vaginitis often cause a vaginal pH higher than 4.5.
Whiff test. Several drops of a potassium hydroxide (KOH) solution are added to a sample of the vaginal discharge. A strong fishy odor from the mix means bacterial vaginosis is present.
KOH mount: A sample of the vaginal discharge is placed on a slide and mixed with a solution of potassium hydroxide (KOH). The KOH kills bacteria and cells from the vagina, leaving only yeast for a yeast infection.
It may also be used in a rape investigation to detect the presence of sperm.

Limitation of wet mount or vaginal smear

Infections like chlamydia, genital warts, syphilis, herpes simplex, and gonorrhea can also affect the vagina, but the causative agents of these diseases can not be covered by this wet mount.
Due to the lack of stain, it is difficult to get morphological details.
Inappropriate preparation of the smear may hide parasites.
Improper adjustment of the microscope in relation to the objective may create problems.

Key Notes

A properly prepared wet mount should be thin enough to allow newsprint to be visible.
There is little difference between normal and physiological saline. Physiological saline is 0.85% NaCl were as normal saline is 0.9% NaCl.
Oil immersion examination is also preferred in parasitology for the permanent stained smear of parasites.
Intestinal protozoa can not conform on the basis of a wet mount alone and thus permanent stained smears require to confirm the specific identification of suspected organisms.

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