<prompt> The whiff test is useful in the diagnosis ofTrichomonasBacterial vaginosisCandidaPID  <response>: Bacterial vaginosis AMSEL criteriaNugent criteriaThin, white, yellow, homogeneous discharge.Clue cells on microscopy.pH of vaginal fluid 4.5.Release of a fishy odor on adding alkali--10 potassium hydroxide KOH solution Whiff testAt least three of the four criteria should be present for a confirmed diagnosis.Grade 1 Normal: Lactobacillus morphotypes predominate.Grade 2 Intermediate: Mixed flora with some Lactobacilli present, but Gardnerella or Mobiluncus morphotypes also present.Grade 3 Bacterial Vaginosis: Predominantly Gardnerella andor Mobiluncus morphotypes. Few or absent Lactobacilli.Refer: Novaks Textbook of Gynaecology, 23rd edition 