What are the Amsel criteria?

Four findings: a homogeneous thin grey-white discharge, vaginal pH above 4.5, a positive whiff/amine test (fishy odour with 10% KOH), and clue cells on saline wet-mount microscopy. Three or more of the four meets the criteria for bacterial vaginosis.

How many criteria are needed?

The classic threshold is three of the four. A modified version using two of three (discharge, clue cells, pH above 4.5) exists and is shown as a labelled alternative, but the default is the ≥3-of-4 rule.

Does meeting the criteria diagnose bacterial vaginosis?

The criteria are a documentation aid that supports the clinical assessment. The tool counts findings you obtained; it does not perform the tests, interpret microscopy, or rule out co-infections such as trichomoniasis or candidiasis.

Does the tool recommend treatment?

No. It never names or doses a treatment. Verify management against the current CDC STI treatment guideline or your national protocol.

Does any of the data I enter leave my browser?

No. The scoring runs entirely in your browser; nothing you enter is sent to a server or stored. The print option produces a clean worksheet you can save as a PDF.

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Amsel criteria calculator (bacterial vaginosis)

Count the four Amsel findings — homogeneous discharge, vaginal pH > 4.5, a positive whiff test, and clue cells — against the ≥3-of-4 threshold for bacterial vaginosis. A documentation aid, not a diagnosis — and nothing you enter leaves your device.

Tick each Amsel finding you have obtained and observed. Three or more of the four meets the criteria for bacterial vaginosis. Each finding counts once.

Amsel findings present

Homogeneous thin grey-white dischargeThin, uniform discharge coating the vaginal walls—Vaginal pH greater than 4.5pH above 4.5 on a vaginal swab against pH paper—Positive whiff (amine) testFishy odour released when 10% KOH is added to the discharge—Clue cells on saline wet-mount microscopyEpithelial cells stippled with adherent bacteria (≥20%)—

Findings present

0/ 4

Does not meet the Amsel criteria (threshold ≥3 of 4)

This tool only counts the findings you mark present. It does not perform the pH, whiff, or microscopy tests, interpret your microscopy, or rule out co-infections such as trichomoniasis, candidiasis, or other STIs. The count supports, not replaces, clinical assessment.

Modified variant (alternative, not the default)

A cited modified rule uses two of three findings — homogeneous discharge, clue cells, and pH above 4.5 (the whiff test is not counted). On the findings entered, this variant is not met. The default reading above remains the classic ≥3-of-4 rule.

Documentation aid, not a diagnosis. This tool only counts the findings you mark present against the published Amsel criteria (Amsel et al., Am J Med 1983) — it does not perform the pH/whiff/microscopy tests, interpret your microscopy, diagnose bacterial vaginosis, rule out co-infections (trichomoniasis, candidiasis, other STIs), or recommend any treatment. The count supports, not replaces, clinical assessment. Guidelines and adjunct/molecular tests evolve — verify against the current CDC STI treatment guideline / national protocol.

Privacy: Runs entirely in your browser — nothing you enter is sent to a server or stored.

Criteria and the ≥3-of-4 threshold reproduced from: Amsel Criteria. StatPearls [Internet]. NCBI Bookshelf NBK542319 (reproducing Amsel et al., Am J Med 1983)..

How the Amsel criteria work

The Amsel criteria are the classic clinic-side way to document bacterial vaginosis: a homogeneous thin discharge, a vaginal pH above 4.5, a positive whiff (amine) test, and clue cells on wet-mount microscopy. Three or more of the four meets the criteria. This tool counts the findings you have already obtained and observed; it does not run the tests, read the microscopy, or rule out other causes of discharge — and it never recommends a treatment.

Many teams still note the four findings on a slip of paper. If you run an OB-GYN clinic workflow on Avinya Plus, the same tally can live on the note: build the Amsel findings into a gynaecology template and count them as you go, so the result sits beside the examination instead of on a scratch pad. The arithmetic is the engine's; the diagnosis stays yours.

Frequently asked questions

What are the Amsel criteria?: Four findings: a homogeneous thin grey-white discharge, vaginal pH above 4.5, a positive whiff/amine test (fishy odour with 10% KOH), and clue cells on saline wet-mount microscopy. Three or more of the four meets the criteria for bacterial vaginosis.
How many criteria are needed?: The classic threshold is three of the four. A modified version using two of three (discharge, clue cells, pH above 4.5) exists and is shown as a labelled alternative, but the default is the ≥3-of-4 rule.
Does meeting the criteria diagnose bacterial vaginosis?: The criteria are a documentation aid that supports the clinical assessment. The tool counts findings you obtained; it does not perform the tests, interpret microscopy, or rule out co-infections such as trichomoniasis or candidiasis.
Does the tool recommend treatment?: No. It never names or doses a treatment. Verify management against the current CDC STI treatment guideline or your national protocol.
Does any of the data I enter leave my browser?: No. The scoring runs entirely in your browser; nothing you enter is sent to a server or stored. The print option produces a clean worksheet you can save as a PDF.

Sources

Amsel Criteria. StatPearls [Internet]. NCBI Bookshelf NBK542319 (reproducing Amsel et al., Am J Med 1983).

The four criteria and the ≥3-of-4 threshold are reproduced from StatPearls (NBK542319, after Amsel et al., Am J Med 1983). A modified 2-of-3 variant exists and is shown as a labelled alternative. The count is a documentation aid, not a diagnosis, and does not exclude co-infections. Reviewed against the source on 2026-06-29.

Keep the criteria on the record.

In Avinya Plus you can build the Amsel findings into a gynaecology template, count them automatically, and keep the result on the consultation note. See it on a quick demo.