Trichomoniasis Workup
- Author: Darvin Scott Smith, MD, MSc, DTM&H; Chief Editor: Burke A Cunha, MD more...
Laboratory Studies
Laboratory studies aid in demonstration of the T vaginalis organism and are used to differentiate trichomoniasis from bacterial or fungal infection.
Saline microscopic examination
- Vaginal trichomoniasis is typically diagnosed with microscopy. A vaginal swab sample for saline wet mount evaluation is an easy, valuable, and economical tool, but specificity is limited and the slide should be evaluated immediately.[2] Trichomonas vaginalis on a saline wet mount at 40X on the microscope. Several motile parasites transit through the field, surrounded by white blood cells and squamous epithelial cells.
- Trichomonads, which are ovoid-shaped parasites, are slightly larger than polymorphonuclear lymphocytes (PMNs) and may be identified by their ameboid mobility. Trichomonads cause an inflammatory reaction; therefore, a large number of PMNs are usually present and correlate with the severity of the infection.
- Microscopy yields a sensitivity of 60-70% in the detection of T vaginalis in vaginal secretions.[2] The absence of trichomonads on microscopy does not exclude the possibility of trichomoniasis.
pH testing
- In women with trichomoniasis, the pH of vaginal secretions measured on Nitrazine paper is often elevated (>4.5). However, an elevation in pH is not highly specific. Bacterial vaginosis frequently also elevates the pH.[2]
- Upon application of 10% potassium hydroxide to a vaginal swab sample in the potassium hydroxide (KOH) amine test, a fishy odor is released, which can suggest trichomoniasis or bacterial vaginosis.
Standard culture
- Disadvantages of culture method include testing time and availability.[5]
- Swab is put in broth and incubated anaerobically at 37°C. Growth is usually detected within 48 hours, and samples without growth after 7 days are considered negative for trichomoniasis.[7]
- Culture is especially important for diagnosing trichomoniasis in men since the wet preparation findings are usually negative. Urethral swab, urine, and semen cultures are used to maximize sensitivity.[2]
Papanicolaou (Pap) smear
- Trichomonads may be viewed on Papanicolaou (Pap) smear, but this test yields low sensitivity and should not be relied on for diagnosis (50%). False-positive results are also common with this technique.[5]
Polymerase chain reaction (nucleic acid amplification)
- Polymerase chain reaction (PCR) methods yield a high sensitivity (84%) and specificity (94%). Although not yet widely available, PCR has great diagnostic potential.[5]
Other Tests
Other Food and Drug Administration (FDA)–approved tests for diagnosing trichomoniasis in women include the OSOM Trichomonas Rapid Test (an antigen-based test) and the Affirm VP III (a DNA probe). These tests offer results within 10 and 45 minutes, respectively. Both are more sensitive than wet mount yet less sensitive and specific than culture.[2]
Histologic Findings
Trichomonads may be observed in a saline wet mount of a vaginal swab or secretion in approximately 60-70% of women with trichomoniasis.[2] Trichomonads are ovoid in shape and slightly larger than PMNs. They are identifiable by to their ameboid mobility. Because they cause an inflammatory reaction, a large number of PMNs are usually present, correlating with the severity of the infection.
Forna F, Gülmezoglu AM. Interventions for treating trichomoniasis in women. Cochrane Database Syst Rev. 2003;CD000218. [Medline].
[Guideline] Centers for Disease Control and Prevention (CDC), Workowski KA, Berman SM. Sexually transmitted diseases treatment guidelines, 2006. MMWR Recomm Rep. Aug 4 2006;55:1-94. [Medline].
Soper D. Trichomoniasis: under control or undercontrolled?. Am J Obstet Gynecol. Jan 2004;190(1):281-90. [Medline].
Gerbase AC, Rowley JT, Mertens TE. Global epidemiology of sexually transmitted diseases. Lancet. 1998;351 Suppl 3:2-4. [Medline].
Sobel JD. What's new in bacterial vaginosis and trichomoniasis?. Infect Dis Clin North Am. Jun 2005;19(2):387-406. [Medline].
Miller M, Liao Y, Gomez AM, Gaydos CA, D'Mellow D. Factors associated with the prevalence and incidence of Trichomonas vaginalis infection among African American women in New York city who use drugs. J Infect Dis. Feb 15 2008;197(4):503-9. [Medline].
Patel SR, Wiese W, Patel SC, Ohl C, Byrd JC, Estrada CA. Systematic review of diagnostic tests for vaginal trichomoniasis. Infect Dis Obstet Gynecol. 2000;8(5-6):248-57. [Medline].
Huppert JS. Trichomoniasis in teens: an update. Curr Opin Obstet Gynecol. Oct 2009;21(5):371-8. [Medline].
Laga M, Manoka A, Kivuvu M, et al. Non-ulcerative sexually transmitted diseases as risk factors for HIV-1 transmission in women: results from a cohort study. AIDS. Jan 1993;7(1):95-102. [Medline].
Moodley P, Wilkinson D, Connolly C, et al. Trichomonas vaginalis is associated with pelvic inflammatory disease in women infected with human immunodeficiency virus. Clin Infect Dis. Feb 15 2002;34(4):519-22. [Medline].
Grodstein F, Goldman MB, Ryan L, et al. Relation of female infertility to consumption of caffeinated beverages. Am J Epidemiol. Jun 15 1993;137(12):1353-60. [Medline].
Shafir SC, Sorvillo FJ, Smith L. Current issues and considerations regarding trichomoniasis and human immunodeficiency virus in African-Americans. Clin Microbiol Rev. Jan 2009;22(1):37-45, Table of Contents. [Medline].
Mann JR, McDermott S, Zhou L, Barnes TL, Hardin J. Treatment of trichomoniasis in pregnancy and preterm birth: an observational study. J Womens Health (Larchmt). Apr 2009;18(4):493-7. [Medline].
[Guideline] ACOG Practice Bulletin. Clinical management guidelines for obstetrician-gynecologists, Number 72, May 2006: Vaginitis. Obstet Gynecol. May 2006;107(5):1195-1206. [Medline].
Burtin P, Taddio A, Ariburnu O, et al. Safety of metronidazole in pregnancy: a meta-analysis. Am J Obstet Gynecol. Feb 1995;172(2 Pt 1):525-9. [Medline].
Guenthner PC, Secor WE, Dezzutti CS. Trichomonas vaginalis-induced epithelial monolayer disruption and human immunodeficiency virus type 1 (HIV-1) replication: implications for the sexual transmission of HIV-1. Infect Immun. Jul 2005;73(7):4155-60. [Medline]. [Full Text].
Nanda N, Michel RG, Kurdgelashvili G, et al. Trichomoniasis and its treatment. Expert Rev Anti Infect Ther. Feb 2006;4(1):125-35. [Medline].
Radonjic IV, Dzamic AM, Mitrovic SM, Arsic Arsenijevic VS, Popadic DM, Kranjcic Zec IF. Diagnosis of Trichomonas vaginalis infection: The sensitivities and specificities of microscopy, culture and PCR assay. Eur J Obstet Gynecol Reprod Biol. May 1 2006;126(1):116-20. [Medline].
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