VAGINAL WET MOUNT EXAMINATION

Effective Date: 
Wed, 08/07/2013
Reviewed: 
Tue, 01/10/2017
Revised: 
Wed, 08/07/2013
Policy: 

 Purpose and Scope:

A vaginal wet mount (sometimes called a vaginal smear) is a test to find the cause of vaginitis, or inflammation of the vagina and the area around the vagina (vulva).
Vaginitis is often caused by an infection, but it may also be caused by a reaction to vaginal products such as soap, bath oils, spermicidal jelly, or douches. Vaginitis may cause symptoms such as vaginal itching, pain, or discharge.
Infections that can cause vaginitis are common and include:
• Yeast infection. A vaginal yeast infection is caused by a type of yeast called Candida albicans. A yeast infection is also called a candida infection, or candidiasis. A vaginal yeast infection often causes itching and a white, lumpy discharge that looks like cottage cheese. It also causes pain with sexual intercourse. A yeast infection is not a sexually transmitted disease (STD).
• Trichomoniasis. Trichomoniasis is a disease caused by a parasite (Trichomonas vaginalis). It is sometimes called trichomonas infection, trichomonal infection, or simply trich (say "trick"). Trichomoniasis causes a vaginal discharge that is yellow-green, foamy, and bad-smelling. Pain with sex or urination may be present. Lower belly pain may also be present. Trichomoniasis is spread by sexual contact and is an STD.
• Bacterial vaginosis. Bacterial vaginosis is a change in the balance of bacteria that are normally present in the vagina. The vaginal discharge is thin and milky with a strong fishy odor. Many women have no symptoms. Bacterial vaginosis is not an STD.
A vaginal sample may be tested by:
• Wet mount. A sample of the vaginal discharge is placed on a glass slide and mixed with a salt solution. The slide is looked at under a microscope for bacteria, yeast cells, trichomoniasis (trichomonads), white blood cells that show an infection, or clue cells that show bacterial vaginosis.
• 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.

Procedure: 

Procedure

Proper specimen collection and handling of vaginal samples is crucial for accurate results. The vaginal vault and walls should be swabbed using one or two swabs. If any fluid has pooled in other areas, these areas should be swabbed as well. The swabs should then be placed in a tube containing 0.5 ml saline and examined within two hours of collection. The sample should remain at room temperature.

After obtaining the sample, it is equally important to properly prepare the slide for examination. The direct, unstained slide should be prepared as follows:
1. Vigorously mix the swab(s) in and out of the saline making sure to collect all the material adhering to the side of the tube.
2. Remove the swab from the saline and depress onto a clean, dry microscope slide expressing a small amount of fluid.
3. Coverslip the sample and examine under a microscope.

Begin the microscopic review of the slide by examining the saline preparation. The examination should begin using the 10x objective noting cellular distribution and obvious cellular and fungal elements. The 40x objective is used to identify the presence of white and red blood cells, quantity and type of bacteria present, clue cells, motile Trichomonas, yeasts, and fungal hyphae.
“Whiff test” is performed by adding a drop of 10% KOH to a drop of wet mount fluid. A "fishy" or amine odor is characteristic in the presence of Trichomonas vaginalis and Gardnerella vaginalis.

 

ELEMENT RARE HPF 1+ (OCC) HPF 2+ (FEW)HPF 3+ (MOD) HPF 4+ (MANY) HPF
WBCs 0-2 2-5 5-10 10-20 >20
RBCS 0-2 1-3 3-5 5-10 >10
BACTERIA 0-2 2-5 5-10 10-20 >20
EPITHELIAL CELLS 0-2 2-5 5-10 10-20 >20
YEAST 0-2 2-5 5-10 10-20 >20
CLUE CELLS 0-2 2-5 5-10 10-20 >20
TRICHOMONAS 0-2 2-5 5-10 10-20 >20
Key Points: 

Reagents and Supplies:
• Microscope slide
• Microscope with low power and high dry
• Sterile saline
• Cotton or polyester swab
• Sterile test tube or Swube
• Disposable pipets
• 10% KOH
 

REFERENCES
Mass, D. "Ensuring Correct Diagnosis in Testing for Vaginitis." Medical Office Report; Volume XI (3): 2-3.
Murry, PR et al. Manual of Clinical Microbiology. 6th ed. Washington, DC: ASM; 1995.