A. What reagent is added to the vaginal swab to perform the Whiff test? B. What smell is distinguishable if the Whiff test is positive?
The correct answer and explanation is:
A. What reagent is added to the vaginal swab to perform the Whiff test?
Correct Answer: 10% potassium hydroxide (KOH)
B. What smell is distinguishable if the Whiff test is positive?
Correct Answer: A fishy or amine-like odor
Explanation (Approximately 300 words):
The Whiff test, also known as the amine test, is a simple and rapid bedside diagnostic procedure used primarily to help diagnose bacterial vaginosis (BV). BV is the most common cause of abnormal vaginal discharge in women of reproductive age and is caused by an imbalance in the normal vaginal flora, particularly a reduction in lactobacilli and an overgrowth of anaerobic bacteria such as Gardnerella vaginalis.
A. Reagent Used:
To perform the Whiff test, a few drops of 10% potassium hydroxide (KOH) solution are added to a sample of vaginal discharge, usually obtained with a swab. KOH is a strong alkaline solution that breaks down proteins and facilitates the release of volatile amines produced by the anaerobic bacteria present in BV.
B. Positive Result – Fishy Odor:
If volatile amines (such as putrescine, cadaverine, or trimethylamine) are present in the vaginal discharge, their release upon KOH addition results in a characteristic “fishy” or amine odor. This odor is considered a positive Whiff test and supports the diagnosis of bacterial vaginosis when correlated with other clinical findings.
The Whiff test is one component of the Amsel criteria for diagnosing BV. A diagnosis is typically made if three out of four of the following criteria are met:
- Homogeneous, thin, grayish-white vaginal discharge
- Vaginal pH greater than 4.5
- Positive Whiff test (fishy odor with 10% KOH)
- Presence of clue cells on microscopic examination
The test is inexpensive, quick, and useful in low-resource settings. However, it should be interpreted in combination with other clinical findings for accuracy.