Bacterial Vaginosis: Likelihood Ratios

Introduction: None written.

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The likelihood ratios of findings for Bacterial Vaginosis are listed below. See the left navigation bar to change the display.

Good Positive and Negative Likelihood Ratios

Finding	+LR	-LR	Comments, Study
Amsel Criteria	91	0.1	3/4: thin, white, homogeneous discharge clue cells pH > 4.5 + Whiff test for Nugent score 7-10 Study: J Clin Microbiol. 2005 Mar;43(3):1304-8. PMID: 15750100
BVBlue Point-of-Care Test	17.6	0.1	This is a test for sialidase activity. Study: J Clin Microbiol. 2005 Mar;43(3):1304-8. PMID: 15750100
Vaginal pH	4.4	0.1	pH > 4.5 Study: The Nugent method is a standardized point scoring system (scores from 0 to 10) based on the presence of three bacterial morphotypes: large gram-positive rods (Lactobacillus spp.), small gram-negative or gram-variable coccobacilli (Gardnerella and anaerobic spp.), and curved gram-variable rods (Mobiluncus spp.) (16). A Nugent score (NS) of 0 to 3 is classified as the presence of normal flora, an NS of 4 to 6 is classified as the presence of an intermediate increase in flora (intermediate flora), and an NS of 7 to 10 is classified as BV.
Clinical diagnosis	2.7	0.3	The clinical examination included a speculum examination for observation of mucopurulent cervicitis and evaluation of secretions for color, viscosity, and homogeneity. Vaginal specimens were collected for wet-prep microscopy (normal saline and 10% potassium hydroxide slides), whiff (amines) test using 10% potassium hydroxide added to the vaginal secretions, and determination of vaginal secretion pH (Phenazine Paper, Decon Laboratories, Inc., King of Prussia, PA). Study: Obstet Gynecol. 2009 Jan;113(1):89-95. PMID: 19104364

Good Positive Likelihood Ratio

Clue Cells

3.4

0.6

on vaginal wet mount: >20%

Another study evaluating for "clue cells present" gave sens=96%, spec=99%

Study: Infect Dis Obstet Gynecol. 2001;9(2):105-11. PMID: 11495550

alt: J Clin Microbiol. 2005 Mar;43(3):1304-8. PMID: 15750100

Poorly Diagnostic Findings

Whiff Test

0.5

1.1

Adding 10% KOH to the vaginal discharge yields a fishy odor

(NOT diagnostic!!)

Study: Infect Dis Obstet Gynecol. 2001;9(2):105-11. PMID: 11495550

Findings With Unspecified Accuracy

Nugent Criteria

No accuracy specified.

on Gram stain, Gardnerella and/or Mobiluncus predominate with few or no Lactobacilli

The Nugent method is a standardized point scoring system (scores from 0 to 10) based on the presence of three bacterial morphotypes: large gram-positive rods (Lactobacillus spp.), small gram-negative or gram-variable coccobacilli (Gardnerella and anaerobic spp.), and curved gram-variable rods (Mobiluncus spp.) (16). A Nugent score (NS) of 0 to 3 is classified as the presence of normal flora, an NS of 4 to 6 is classified as the presence of an intermediate increase in flora (intermediate flora), and an NS of 7 to 10 is classified as BV.

Study: J Clin Microbiol. 2005 Mar;43(3):1304-8. PMID: 15750100