Authors: Gia Garrett, MS4 and Jennifer M. Keller, MD MPH
Date: June 25, 2018

Clinical Scenario

A 28 y/o G0 established patient presents to your clinic with a complaint of three days of copious, thin, clear to whitish discharge with a “funny” odor. This is the first time she has had these symptoms. She denies any vaginal or vulvar burning, pruritus, dysuria, or dyspareunia. Her LMP was one week ago, she uses a Levonorgestrel IUD for contraception, and is monogamous with one male partner. She denies douching, new soaps or detergents, and has not tried over the counter methods for treatment.

Scenario A

Her speculum exam is unremarkable other than increased discharge, and you obtain samples of the discharge for testing vaginal pH, performing an amine “whiff” test, and microscopy using saline wet mount and KOH prep. The sample has a positive amine test, a pH of 5, and clue cells are visualized on the wet prep slide. You prescribe her Metronidazole 500 mg BID for 7 days and tell her to call the office if her symptoms do not resolve.

Scenario B

Her speculum exam is unremarkable other than increased discharge, and you obtain a vaginal swab to send to the lab for nucleic acid amplification testing (NAAT).  You check the “VG Plus” box on the lab slip without being entirely sure what that test includes.You receive her test results one week later that are positive for Bacterial Vaginosis. The lab also tested for Candida Albicans, Candida Glabrata, Trichomoniasis, Chlamydia and Gonorrhea.  You call her with the results and prescribe her Metronidazole 500 mg BID for 7 days, saying she can call the office if her symptoms do not resolve.

Discussion Questions

  • What is the appropriate method of diagnosis when a patient presents with nonspecific vaginal discharge and why?
  • Does the convenience and increased specificity of the nucleic acid probe justify the increased cost and delayed diagnosis?

Costs Scenario A

Level III Established Patient Physician Visit Charge- $84
Office wet prep CPT 87210 Charge $20.00 (Billing office data)
Slide/Coverslip: $0.10 * Price on Amazon
pH testing Strip -- $0.10 *Price on Amazon
Metronidazole 500mg (14 tablets cost $10.00 or under at Walgreens and Rite Aid per
Total: $94.00
*Assuming the facility already has a microscope

Costs Scenario B

Level III Established Patient Physician Visit Charge- $84.00
NuSwab Vaginitis (VG+) Charge-$ 807.75 (Labcorp website)
Total: $891.75

Teaching Moment

Bacterial Vaginosis, Vaginal Candidiasis, and Trichomonas Vaginalis are the most prevalent causes of Vaginitis. This patient has Bacterial Vaginosis as defined by three out of four of Amsel’s Criteria: abnormal gray discharge, vaginal pH greater than 4.5, a positive amine test, and more than 20% of the epithelial cells being clue cells. The gold standard for diagnosing Bacterial Vaginosis remains Gram staining with a Nugent score greater or equal to 7 or meeting Amsel’s criteria, which has a sensitivity of 92% and specificity of 75%. This method also confers the advantage of in-office diagnosis and treatment upon presentation. 

In contrast, testing with nucleic acid amplification tests confers higher sensitivity and specificity than microscopic diagnosis, but is much more costly and can delay diagnosis and treatment. This patient is presenting with symptoms for the first time, has no complicating health factors such as pregnancy, menopause, or immunodeficiency, and has a clear clinical presentation. Studies have shown that syndromic diagnosis alone has low to moderate specificity and is insufficient to determine the etiology of vaginitis. Beginning with microscopy is appropriate and cost effective. If microscopic analysis is indeterminate and/ or her clinical picture is complicated by self-treatment, the additional cost of sending a swab for NAAT may be worth the diagnostic clarity.


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  6. NuSwab New approach to testing for infections of the genital tract
  7. Lab Corp Net Fee Schedule Period: September 1, 2015 through August 31, 2017