What are the Amsel criteria for diagnosis of bacterial vaginosis (BV)?

Updated: Sep 25, 2017
  • Author: Philippe H Girerd, MD; Chief Editor: Michel E Rivlin, MD  more...
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Answer

Demonstrating three of the following four Amsel's criteria is considered necessary to diagnose BV most accurately [2] :

  • Demonstration of clue cells on a saline smear is the most specific criterion for diagnosing BV. Clue cells are vaginal epithelial cells that have bacteria adherent to their surfaces. The edges of the squamous epithelial cells, which normally have a sharply defined cell border, become studded with bacteria. The epithelial cells appear to be peppered with coccobacilli.

  • A pH greater than 4.5 indicates infection, and pH may be elevated in up to 90% of patients with BV.

  • Characteristic discharge appearance is thin, gray, and homogeneous.

  • The whiff test may be positive in up to 70% of BV patients. This test is performed by placing a drop of 10% KOH on the speculum after the vaginal examination or mixing vaginal fluid with a drop of KOH on a microscope slide. The KOH, by virtue of its alkaline properties, causes the release of volatile amines from the vaginal fluid. The amines are products of anaerobic bacterial metabolism.


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