Microscopic analysis of vaginal fluid provides immediate insight into the balance of the vaginal environment. Healthcare providers examine a sample under a microscope, looking for specific cellular indicators that point toward a diagnosis. The presence of the clue cell is one of the most important diagnostic indicators. This cell type acts as a clear microscopic marker for a particular type of vaginal infection.
What Exactly Are Clue Cells
A clue cell is a vaginal epithelial cell that has become heavily coated with a dense layer of bacteria. These bacteria are primarily the coccobacilli, Gardnerella vaginalis, and other anaerobic organisms. The distinct appearance provides a direct microscopic “clue” to a specific diagnosis, hence the name “clue cell.”
When viewed under a microscope, the adherence of these bacteria gives the epithelial cell a characteristic stippled or granular appearance, often described as having a “ground black pepper” look. This dense bacterial coverage obscures the normally sharp, distinct borders of the epithelial cell, making the edges look “fuzzy” or indistinct. This unique morphology distinguishes the clue cell from a healthy epithelial cell, whose surface is typically smooth.
The Purpose of the Wet Prep Test
Clue cells are identified during a rapid, in-office procedure known as a wet preparation or wet mount. This test is the microscopic examination used to evaluate the cause of abnormal vaginal discharge, helping to distinguish between common infections. The procedure is simple: a small sample of vaginal discharge is collected, mixed with saline solution on a glass slide, and immediately examined under a microscope.
During the wet prep, the healthcare provider specifically looks for the presence of clue cells, among other findings like yeast or motile organisms. For the finding to be considered significant, a specific threshold must be met for diagnosis. The observation is considered positive when more than 20% of the epithelial cells visible on the slide are identified as clue cells. This microscopic finding is one of the four established Amsel criteria used to make a clinical diagnosis.
The Diagnosis: Bacterial Vaginosis
The presence of clue cells is considered the hallmark diagnostic sign for Bacterial Vaginosis (BV). BV is a common vaginal condition caused by an imbalance in the vaginal flora. In this condition, the normal, protective Lactobacillus species are significantly reduced, allowing for the overgrowth of various anaerobic bacteria, including Gardnerella vaginalis.
The overgrowth of these organisms leads to the clinical symptoms of BV after they adhere to the vaginal epithelial cells to form clue cells. The condition is not inflammatory, meaning the microscopic sample typically lacks the high number of white blood cells seen in other infections. This lack of inflammation helps differentiate BV from other infections like trichomoniasis.
Women with BV often experience a thin, homogeneous, grayish-white vaginal discharge. A noticeable symptom is a distinct “fishy” odor, which may become stronger after intercourse or during menstruation. The finding of clue cells, combined with the presence of this discharge and a vaginal pH greater than 4.5, confirms the diagnosis.
Treatment and Management
Treatment for Bacterial Vaginosis focuses on restoring the balance of the vaginal flora. The standard medical response involves prescription antibiotics, administered either orally or topically as a gel or cream. Common antibiotics prescribed include metronidazole, clindamycin, and tinidazole.
It is important for the prescribed course of antibiotics to be completed entirely, even if symptoms begin to clear up quickly. Stopping treatment prematurely increases the likelihood of the condition returning. BV is known to have a high rate of recurrence, often returning within months even after successful initial treatment. For persistent or recurrent cases, a healthcare provider may recommend an extended course of topical treatment or explore alternative management strategies.