How Accurately Is Vaginitis Diagnosed?
Abstract & Commentary
By Frank W. Ling, MD, Clinical Professor, Department of Obstetrics and Gynecology, Vanderbilt University School of Medicine, Nashville, is Associate Editor for OB/GYN Clinical Alert.
Dr. Ling reports no financial relationship to this field of study.
Synopsis: Under research conditions, accurate diagnosis of common causes of vaginitis was < 85% sensitive.
Source: Lowe NK, et al. Accuracy of the clinical diagnosis of vaginitis compared with a DNA probe laboratory standard. Obstet Gynecol 2009;113: 89-95.
The authors sought to determine the accuracy of diagnosing vulvovaginal symptoms related to the three most common causes, i.e., bacterial vaginosis (BV), candidiasis vaginitis (CV), and trichomoniasis vaginalis (TV). They compared standard clinical evaluation (history, physical, visual description of discharge, wet prep, sniff [amine] test, pH) and compared it to a DNA probe technique in a study group of 547 patients. The clinicians were experienced masters-prepared nurse practitioners and the patient population was an active duty military group of women. Patients were treated based on the clinical evaluation, then followed up with telephone or in-person interviews. The DNA probe results were not divulged to the clinicians, and, similarly, the clinical diagnosis in each case was not revealed to those performing the DNA probe.
Clinical diagnosis accuracy was highest for TV and lowest for BV (98.9% and 76.3%, respectively). Sensitivities ranged from a low for BV of 80.8% to 84.6% for TV, while specificities ranged from 70% for BV to 99.6% for TV. Of note, of the 94.1% of patients whose symptoms were relieved at follow-up, 60% of the clinical diagnoses were accurate when compared to the DNA probe, i.e., 40% of the diagnoses were inaccurate, yet the patients' symptoms were relieved.
Commentary
You're asking yourself if this is accurate, aren't you? You're also wondering how you're doing in your practice. If you're a bit cynical, you're even asking yourself, "What difference does it make?" If only 60% of diagnoses are accurate, i.e., match up with the DNA probe diagnosis, yet 94% of patients have symptoms relieved when they are treated clinically without the benefit of the DNA probe results, what's wrong with just continuing the tried and true methods we were taught way back when?
Indeed, this article should cause us at least to think about what we do so routinely. Think back ... Who taught you how to prepare a saline prep, what the purpose of the potassium hydroxide was, what a positive "whiff" test means? Are you still performing the same procedures when a woman complains of a discharge? Is the DNA probe technology (aka Affirm VPIII Microbial Identification Test) a better mousetrap?
The study was conducted in a research setting that should have maximized the accuracy of clinical diagnosis. The clinicians did not have the time pressures that the grind of daily practice demands, and the protocol for history, physical, and laboratory assessment in all likelihood exceeded what we do in our daily clinical activities. Among these symptomatic subjects, 23.4% were prescribed a treatment not supported by DNA analysis. Another 16.1% of patients were not prescribed medication that was indicated based on the DNA technology. Despite these findings, the relief that patients (more than 94%) reported attests to something being done correctly. The authors point out that the analysis might have been different if total follow-up of patients had been achieved. There is also nothing reported regarding relapse/recurrence rates. It is also important to note that the DNA probe is only for Gardnerella vaginalis, such that the true polymicrobial nature of this diagnosis is not factored into the equation.
The reader should know that the office I practice in does utilize the Affirm technology. It is certainly more efficient since it does not require me to take the sample, prepare a wet mount, seek out the microscope, then make a diagnosis. Instead, all I do is take a swab from the vagina and give it to our nursing assistant. The rest is considered routine office protocol. The tests from the office are batched into morning or afternoon "runs," and the patients are called about the results and prescriptions are called in based on the findings. As far as the patient is concerned, the tests are more accurate because they are computerized and the delay in diagnosis, which amounts to only a couple of hours, is not significant. Even though the test is not covered by some insurance plans, the reimbursement from those insurers who do pay easily pays for the cost of the machine and supplies. For patients who come to us after failing self-medication or prescriptions from other providers, the DNA probe is an evaluation that can provide a more accurate diagnosis. As an aside, I certainly don't mind minimizing the number of positive "whiff" tests that I experience.
So I think our take home message is the following: As much as we wish to treat each woman who complains of vaginal discharge based upon the best information possible, we should recognize that the best information is probably not very accurate. Despite that, if our goal is the patient having her problem taken care of, the use of higher technology may not be necessary. The astute clinician should at least consider adding this tool to his workshop, assuming it makes both clinical and financial sense.
The authors sought to determine the accuracy of diagnosing vulvovaginal symptoms related to the three most common causes, i.e., bacterial vaginosis (BV), candidiasis vaginitis (CV), and trichomoniasis vaginalis (TV).You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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