Trichomoniasis: Likelihood Ratios

Introduction: Trichomoniasis is a common sexually transmitted disease caused by Trichomonas vaginalis.

Prevalence

Population / Calculator	Prevalence	Comments / Study / Link
Women age 14-49, United States	3%	Trichomonas vaginalis infection detected by PCR of self-collected vaginal swabs by 3754 women. Clin Infect Dis. 2007 Nov 15;45(10):1319-26.
	66%
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The likelihood ratios of findings for Trichomoniasis are listed below. See the left navigation bar to change the display.

Good Positive and Negative Likelihood Ratios

Finding	+LR	-LR	Comments, Study
Transcription-mediated amplification testing	49	0	Study: PMID: 17578778
Affirm VP III Microbial Identification System	90	0.1	Compared with culture on Diamond's medium and wet-mount identification of T. vaginalis. Test takes 45" to read. Study: PMID:8623867
OSOM Trichomonas Rapid Test	44	0.1	Dipstick assay that takes 10" to read. Study: PMID:15695664
Culture on Diamond's Medium	19	0.1	Study: UptoDate: http://www.uptodate.com/online/content/topic.do?topicKey=gen_gyne/28379&selectedTitle=1~30&source=search_result
Clinical diagnosis	211.5	0.2	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
Trichomonads on liquid-based Pap smear	61	0.4	Study: Study: Am J Obstet Gynecol. 2003 Feb;188(2):354-6; PMID: 12592239
Trichomonads on liquid-based Pap smear	19	0.4	Incidental finding on Pap smear. Recommend treatment if prevalence of trichomoniasis is >= 20%. Based on meta-analysis of multiple studies, 1976-1998. Study: Am J Med. 2000 Mar;108(4):301-8; PMID: 11014723

Poorly Diagnostic Findings

Finding	+LR	-LR	Comments, Study
Vaginal pH	1.1	0.9	pH >4.5 Study: Hopkins Antibiotics Guide
Wet Mount	Sensitivity = 65%		of vaginal discharge, looking for motile trichomonads Study: Hopkins Antibiotics Guide
Strawberry Cervix	Sensitivity = 5%		specificity not mentioned Study: Hopkins Antibiotics Guide