Diagnosing Bacterial Vaginosis
Professional GP advice, anytime, anywhere
First Steps: Clinical Assessment
When you visit your doctor to figure out what’s going on, they’ll start by asking questions and doing a gentle exam to get a clear picture of your symptoms. Here’s what that process looks like in simple terms:
Talking About Your Symptoms
Your doctor will ask you about what you’re experiencing, such as:
What does the discharge look like? (For example, is it thin and greyish-white?)
When did it start, and how long has it been happening?
Are you having other symptoms, like itching, irritation, or a strong odour?
Have you recently had sexual activity, used douches, or taken antibiotics?
These questions help your doctor understand what might be causing your symptoms.
Physical Exam
The doctor may use a tool called a speculum to gently look inside your vagina. This helps them see:
The type of discharge you have.
Any changes in the vaginal tissue, like redness or sores.
If your symptoms look like they might be caused by something else (for example, a thick, white, cottage-cheese-like discharge could mean a yeast infection, or a green, frothy discharge might suggest trichomoniasis), your doctor may suggest additional tests to figure out the exact cause.
UK Diagnostic Criteria
In the UK, frontline clinicians often apply Amsel’s criteria at point of care, supplemented (where available), by microscopy or laboratory scoring systems . This requires meeting at least 3 of the below criteria:
Homogeneous, thin, grey-white discharge coating the vaginal walls
Vaginal pH >4.5 (measured with pH paper)
“Whiff” test positive: a fishy amine odour when a drop of 10% potassium hydroxide (KOH) is added to the discharge
Clue cells on wet-mount microscopy: epithelial cells studded with bacteria, obscuring cell borders
Few Tips
Hygiene Advice: Avoid douching and scented soaps.
Partner Treatment: Not routinely recommended unless symptomatic.
Re-Evaluation: If symptoms persist beyond one week of treatment, re-assess with microscopy or refer to a specialist clinic.
Conclusion
Diagnosing BV in the UK hinges on combining clinical acumen with simple, rapid tests, notably Amsel’s criteria — backed up by laboratory scoring when needed. By following BASHH and NICE guidelines, clinicians ensure accurate diagnosis, appropriate treatment, and reduced recurrence, safeguarding women’s reproductive health.
What Is Bacterial Vaginosis?
BV arises when the normal balance of vaginal bacteria is disrupted. In healthy vaginas, Lactobacillus species dominate, producing lactic acid to keep the pH low (≤4.5) and thwart overgrowth of bad bacteria. In BV, an increase of anaerobic organisms (eg. Gardnerella vaginalis, Prevotella, Mobiluncus) leads to:
Thinning or homogeneous discharge
Raised vaginal pH, ie. lower acidic levels, creating a thriving environment for bad bacteria
Release of volatile amines (putrescine, cadaverine), ie. foul smelling molecules
Why Accurate Diagnosis Matters
Avoid Overtreatment: Treating non-BV discharge (e.g., candidiasis) with antibiotics can worsen symptoms or breed resistance.
Prevent Complications: In pregnancy, untreated BV is linked to preterm labour and low birth weight.
Tailor Management: Recurrent BV may require a different approach (e.g., suppressive regimens).
Explore our Vaginal Health Self Assessment
