Lab Test

Wet Prep Exam

Trichomonas, Trich, Trichomonas vaginalis, Clue Cells, Yeast, Affirm, Vaginosis, Vaginitis

Test Codes





Female genital specimens should be tested with the AFFIRM system (see Vaginosis Screen).

Specimen Collection Criteria

Collect: Vaginal specimen using the ESwab transport system or a red VACUETTE PBS tube paired with a polyester swab.

Physician Office/Draw Specimen Preparation

Maintain specimen at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F) prior to courier transport. Transport specimens to the Laboratory within 2 hours of collection.

Preparation for Courier Transport

Transport: ESwab, saline or PBS at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F).

Rejection Criteria

  • Specimens collected with cotton tips on wooden shafts.
  • Specimens collected from sources other than the vaginal cavity.

In-Lab Processing

Specimens at room temperature (20-26°C or 68-78.8°F) or refrigerated must be tested within 2 hours of collection. Specimens frozen at -20°C/-4°F or below are unacceptable.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 2 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Room Temperature (20-26°C or 68-78.8°F): 7 days


Dearborn Microbiology Laboratory
Farmington Hills Microbiology Laboratory
Grosse Pointe Microbiology Laboratory
Lenox Laboratory
Livonia Laboratory
Royal Oak Microbiology Laboratory
Taylor Microbiology Laboratory
Troy Microbiology Laboratory
Trenton Microbiology Laboratory
Wayne Laboratory


Sunday – Saturday.
STAT results available within 1 hour of receipt in the Microbiology Laboratory. Routine results available within 4 hours of receipt in the Microbiology Laboratory.

Reference Range

No yeast seen. No 'Clue' cells seen. No Trichomonas seen

Note: A false negative result may occur if the specimen is inadequately collected.

Test Methodology

Microscopic analysis (clue cells, yeast, and trichomonas).


  • A wet prep exam of vaginal fluid can demonstrate the presence of specialized epithelial cells coated with bacteria known as 'clue cells' and yeast. Bacterial vaginosis is a clinical syndrome characterized by a shift in the vaginal microbiota. Yeast is an indicator of yeast vaginitis.
  • A positive antigen is diagnostic of infection or carriage. T. vaginalis is site specific and cannot survive outside the urogenital system. While vaginitis is the most common presentation, other complications include dysuria, endometriosis, infertility, low birth weight, and cervical erosion.

Clinical Utility

Clinical manifestations are not reliable criteria for the diagnosis of trichomoniasis. Demonstration of the parasite is required for accurate diagnosis of infection. If classic features such as a frothy vaginal discharge are used alone for diagnosis of trichomoniasis, 88% of infected women will not be diagnosed and 29% of uninfected women will be incorrectly diagnosed as having the parasite.


  1. Leber, A.L. and S. Novak-Weekley. 2015. Intestinal and Urogenital Amebae, Flagellates, and Cliates. In: Jorgensen, J.H. et. al. (eds.). Manual of Clinical Microbiology. 11th edition. ASM Press. Washington, D.C., pg. 2399-2425.

CPT Codes

87808, 87210.


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