Clue cells are the most reliable indicators of bacterial vaginosis (BV). These vaginal epithelial cells contain many attached bacteria, which create a poorly defined stippled cellular border. The positive predictive value of this test for the presence of BV is 95 percent.Clinical criteria for diagnoses include,Homogeneous white, noninflammatory dischargeMicroscopic presence of clue cellsVaginal discharge with pH >4.5Fishy odor with or without addition of 10% potassium hydroxideThree of these 4 criteria are required to make a clinical diagnosis of bacterial vaginosis. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 3. Gynecologic Infection. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.