Test card is positive step in vaginitis diagnosis
What is your current procedure to diagnose vaginitis? Do you rely on laboratory pH paper to determine pH imbalance, potassium hydroxide to detect amines, and a wet mount slide under the microscope to make a definitive diagnosis? Or is the process so time-consuming that diagnosis is based on a visual exam, which may lead to improper treatment?
"In my experience, the inconvenience of using pH paper and the whiff test leads to most clinicians not bothering to do them," notes David Soper, MD, professor and director of the division of gynecology at the Medical University of South Carolina in Charleston. "Unfortunately, in making the diagnosis of vaginitis, knowing the results of the pH and amines test makes one a better microscopist, and diagnostic microscopy is the way we make the diagnosis of bacterial vaginosis [BV], vaginal yeast infections [candidiasis], and trichomoniasis vaginitis."
Clinicians now can use the FemExam pH and Amines TestCard from CooperSurgical of Shelton, CT, to eliminate the need for pH paper and potassium hydroxide. By placing a drop of vaginal fluid on the disposable, credit card-sized device, clinicians get a reading in two minutes whether the patient tests positive or negative for elevated pH and presence of volatile amines.
"I believe the FemExam card will make it easier for clinicians to do the tests and, therefore, make them better at the microscope," says Soper. "This translates into better diagnostic accuracy and, therefore, better care for the patient."
The FemExam card originally was developed by Litmus Concepts of Santa Clara, CA. (See Contra cep tive Technology Update, September 1997, p. 115, for information on the Food and Drug Administration approval of the testing device.) CooperSurgical, which has acquired the TestCard technology, has announced plans to introduce individual tests for BV, candidiasis, and trichomoniasis, the three most common forms of vaginitis.
When a swab containing unprocessed vaginal fluid is rubbed across the two test areas of the card, chemical changes will result in a positive or negative sign to appear in the test areas.
Two plus signs on the FemExam card suggest the diagnosis of BV, Soper explains. Two negative signs in the test areas suggest the diagnosis of yeast in a symptomatic patient. This knowledge can lead the clinician to look for either the "clue cells" associated with BV or the fungal elements of yeast infection.
Cost of a FemExam card averages between $5.25 and $6.50, depending on the purchased amount, according to company figures. The card technology features built-in controls to ensure accuracy and requires no added equipment, special storage, or disposal conditions.
Serious health risk link
Vaginitis, especially BV, has been the subject of increasing health concerns. BV has been linked with adverse outcomes in pregnancy, such as premature rupture of the membranes, preterm labor, and preterm birth, and the organisms found in BV also are frequently present in postpartum or post-cesarean endometritis, according to the Cen ters for Disease Control and Prevention (CDC) in Atlanta.1 Annual estimated costs for BV-associated complications in pregnancy are estimated at $500 million to $1 billion annually.2
"We have had a lot of discussion in Maryland about the role of undiagnosed, untreated infections, especially BV in preterm pregnancy and infant mortality," says Willa Brown, MD, MPH, director of the Howard County Health Depart ment’s bureau of personal health in Columbia, MD. "An accurate, rapid, inexpensive test would help define this problem and, with early treatment, reduce the morbidity from these infections, especially in pregnant women."
In a study by researchers with the CDC’s National Center for Infectious Disease and Emory University in Atlanta, 100 women presenting for initial prenatal visits were evaluated for BV using Gram stain of vaginal secretions, standard clinical criteria, and the FemExam card.
Gram stains were read by microbiologists, and BV was diagnosed using standard criteria. BV was diagnosed on the basis of Eschenbach’s modification of Amsel’s criteria if "clue cells" were present on wet mount and a positive amine odor was present upon testing with potassium hydroxide solution. BV was diagnosed using the card if both the pH icon and amine icon displayed a plus sign. Sensitivity, specificity, positive predictive value, and negative predictive values were calculated comparing the two methods with Gram-stain diagnosis as the "gold standard."
The prevalence of BV in the study population was 28% using Gram-stain criteria. When the Gram stain was used as the "gold standard" for diagnosis, results provided a sensitivity of 75%, a specificity of 94.4%, a positive predictive value of 84%, and a negative predictive value of 90.7%. The TestCard’s numbers, in comparison, were 78.6%, 91.7%, 78.6%, and 91.7%, respectively.
The researchers, lead by Mark Newman, MD, a guest investigator with the National Center for Infectious Disease, concluded that the FemExam TestCard demonstrates "a diagnostic utility at least equal to the wet prep/vaginal pH/whiff-test criteria currently used to diagnose BV in an obstetric population."
Anita Nelson, MD, medical director of the Women’s Health Care Clinic at the Harbor-University of California in Los Angeles Medical Center in Torrance, reminds clinicians that while the FemExam card does help diagnose vaginitis, a wet mount slide reading still is necessary to rule out a second, underlying infection. "It does give us a bridge as we move to the antigen test, which is what we really need to have if people are not going have a colposcope in their office."
References
1. 1998 Guidelines for Treatment of Sexually Transmitted Diseases. MMWR 1997; 47(RR-1).
2. Oleen-Burkey MA, Hillier SL. Pregnancy complications associated with bacterial vaginosis and their estimated costs. Infect Dis Obstet Gynecol 1995; 3:149-157.
Resource
For more on the FemExam TestCard, contact:
• CooperSurgical, 15 Forest Parkway, Shelton, CT 06484. Telephone: (800) 848-0033.
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