Summary Gutman et al. Evaluation of clinical methods...Articles for review.Literature review.Sexually Transmitted Diseases Diagnostics Initiative (SDI)

Literature reviews > Articles for review > Gutman et al. Evaluation of clinical methods...

Two clinical criteria instead of four can be used to diagnose bacterial vaginosis.

Evaluation of clinical methods for diagnosing bacterial vaginosis.
Gutman RE, Peipert JF, Weitzen S, Blume J.
Obstetrics & Gynecology 2005;105:551-56

Summary:

Question

Can the current clinical criteria used for diagnosing bacterial vaginosis (BV) (Amsel method) be simplified by using 2 clinical criteria, rather than the standard 3 of 4 criteria?What is the performance of the FemExam card when compared with Amsel criteria for the diagnosis of BV?

Design

This article describes a prospective observational study in which the performances of each individual Amsel clinical criterion, combinations of criteria, and the FemExam card were determined for the diagnosis of BV as determined using the Nugent Gram stain score as the gold standard.

Participants

Two hundred sixty-nine women undergoing a speculum examination at various clinics in Women and Infants Hospital were tested.The population was 37.5% white women, 30.4% black women, and 27.6% Hispanic women.Women were excluded if there was a large amount of vaginal bleeding on examination.

Description of Tests and Diagnostic Standard

Vaginal discharge was characterized according to its color and the presence of a thin, homogeneous discharge. Vaginal secretions were taken from the sidewalls with 4 swabs and 1) placed on ColorpHast pH indicator strips, range 4.0 to 7.0 (EM Science, Gibbstown, NJ) to determine vaginal pH, then combined with 2 drops of normal saline on a slide and coverslipped for wet mount microscopy to identify the percentage of clue cells; 2) added to 10% potassium hydroxide to determine release of a fishy amine odor (whiff test); 3) placed on a FemExam card (Cooper Surgical Inc., Trumbull, CT) for the colorimetric detection of vaginal pH >4.7 and the presence of volatile amines; and 4) rolled on a glass slide for Gram staining and evaluation of bacteria according to the Nugent score. A Nugent Gram stain score of >7 was defined as the gold standard diagnosis of BV. A receiver operating characteristic (ROC) curve was generated for pH and percentage of clue cells on wet preparation.

Main Outcome Measures

The sensitivity and specificity for each of the individual criterion, combinations of criteria, Amsel's criteria, and the FemExam card for diagnosis of BV as determined using Nugent Gram stain scores were calculated.

Main Results

The prevalence of BV was 38.7%.The sensitivity and specificity of the various individual and combined criteria for diagnosis of BV as determined by Nugent Gram stain score are shown in the table. Vaginal pH had the highest sensitivity, but the lowest specificity, of all clinical diagnostic criteria. Amine odor had the highest specificity and lowest sensitivity of the individual criteria. The combination of any 2 criteria decreased sensitivity and increased specificity. Based on ROC curves, a pH of 5.0 or greater maximized sensitivity (83%) and specificity (82%), and a cutoff of more than 20% clue cells on saline wet mounts maximized sensitivity (74%) and specificity (86%).

Sensitivity and specificity of individual and combined criteria for the diagnosis of BV as determined by a Nugent Gram stain score of >7 among 269 women

Test	Individual or combined criteria	Performance (%)
Test	Individual or combined criteria	Sensitivity	Specificity
Amsel clinical criteria	Thin homogenous discharge	79	54
	pH >4.5	89	74
	Positive amine odor	67	93
	Clue cells >20%	74	86
	pH >4.5 and thin homogenous discharge	69	86
	pH >4.5 and positive amine odor	64	95
	pH >4.5 and clue cells >20%	69	92
	Clue cells >20% and positive amine odor	63	95
	Clue cells >20% and thin homogenous discharge	61	91
	Positive amine odor and thin homogenous discharge	58	94
	At least 3 of 4 Amsel criteria	69	93
FemExam card	pH positive	88	64
	Amine positive	41	91
	pH positive or amine positive	89	61
	pH positive and amine positive	40	95

Authors' Conclusions

The sensitivity and specificity of each pair of criteria was similar to those observed for Amsel's criteria. This implies that there is no clear advantage to using at least 3 positive of 4 Amsel criteria and supports the hypothesis that the current clinical criteria for diagnosing BV can be simplified by using 2 clinical criteria, without loss of sensitivity or specificity. The findings of this study fail to support routine use of the FemExam card to improve sensitivity and specificity.

An algorithm is recommended that involves initial diagnostic testing for BV with pH, using test paper with a pH range of 4 to 6.Testing for one of the other 3 criteria should then be performed. If one or both tests are negative, additional tests should be performed until a diagnosis is made.

Source of funding: Cooper Surgical for FemExam cards

For correspondence: Robert E. Gutman, 4940 Eastern Avenue, Room 125, Baltimore, MD 21224-2780.E-mail address: rgutman1@jhmi.edu

about SDI | newsletters | grants | publications | literature reviews

WHO Home - WHO Search - TDR Home - SDI Home - SDI Contact us
(c) WHO/OMS 2001