Bacterial vaginosis (BV) is an infection caused by the overgrowth of bacteria in the vagina. While a number of symptoms can be present, there are also signs of the disease that only doctors can identify. These invisible indicators help doctors make the correct diagnosis and offer successful treatment options.
Clue Cells
The National Institutes of Health indicates that a wet mount test can be done to determine if BV is present (see References). This test takes a swab of the vagina walls, collecting a sample of discharge, and is then analyzed for bacteria and other signs of disease. One of the major signs is the presence of clue cells in the test sample. According to the Merck Manual for Healthcare Professionals, clue cells are vaginal epithelial cells that are obscured by bacteria (see References).
Whiff Test Odor
Another sign of BV is the presence of a fishy odor during the whiff test. According to Dr. Barbara Majeroni of the State University of New York at Buffalo, the whiff test is performed by collecting a sample of vaginal secretions and adding potassium hydroxide to the sample (see References). If a fishy odor is detected once the potassium hydroxide is added, BV is usually the cause. But because a positive whiff test can also be a sign of trichomoniasis infection, a definitive diagnosis of bacterial vaginosis should be made using other tests.
Specific Bacteria
According to a 2005 study published in the New England Journal of Medicine, the presence of specific bacteria in vaginal secretions is a sign of BV (see References). When the vaginal secretions of study participants were tested with polymerase-chain-reaction amplification, the women who tested positive had BV-specific bacteria present in their secretions. Women testing negative did not have these bacteria and had high concentrations of healthy bacteria (lactobacilli) in their vaginal secretions.
Change in Vaginal pH
Dr. Barbara Majeroni indicates that a change in vaginal pH is a sign of BV (See Reference 3). Normal vaginal pH is less than 4.5. When BV is present, the vaginal pH is above 4.5. Vaginal pH can be tested by taking a sample of vaginal secretions and measuring their acidity. Because the pH of cervical mucus is often higher than that of vaginal secretions, medical professionals need to exercise care in collecting secretion samples.
Absence of Lactobacilli
According to Dr. Barbara Majeroni, an absence of healthy bacteria in the vaginal secretions can be a sign of BV (see References). These healthy bacteria keep the vaginal environment balanced. When they are absent, bacteria that cause disease are able to grow unchecked and cause infections. This sign is not specific to the disease, so other tests should be performed to confirm the suspicion of BV.
