Diagnosis of Trichomonas vaginalis infection: The sensitivities and specificities of microscopy, culture and PCR assay.
OBJECTIVE
The aim of this study was to compare wet mount-, Giemsa stain-, acridine orange fluorescent stain-, cultivation- and polymerase chain reaction (PCR)-based approaches to establish which method or combination of methods was most effective in the laboratory diagnosis of trichomoniasis.


METHODS
Out of 200 investigated patients with various gynecological complaints, Trichomonas vaginalis infection was detected in 27 (13.5%) by any of methods investigated. Among women with trichomonads, a typical clinical finding was presented in only nine. For analysis of sensitivity and specificity of the methods used, the receiver operating characteristic (ROC) curve concept with culture as a gold standard was applied.


RESULTS
Infection was diagnosed by wet mount in 14 (7.0%) women, by Giemsa stain in 11 (5.5%) and by acridine orange stain in 16 (8.0%) women. In 21 (10.5%) women, it was diagnosed by culture in Diamond's medium, and in 22 (11.0%) by PCR. For the initial diagnosis of trichomoniasis, wet preparation is the test that is widely available in most STD clinics, but its sensitivity is poor (66.67%). Giemsa stain shows a low sensitivity of 52.38%. Acridine orange shows reasonable sensitivity and specificity of 71.43% and 99.44%, respectively. The sensitivity and specificity of PCR (80.95% and 97.21%) did not exceed that of culture.


CONCLUSIONS
With regard to the fact that trichomoniasis can have an atypical or even asymptomatic course, in order to accurately diagnose this disease, microbiological investigation is necessary. Comparison of different methods showed that at least two techniques, such as culture and acridine orange staining, have the potential for better diagnosis of T. vaginalis infection. PCR detection of infection has been demonstrated to be highly specific and sensitive, but its availability and cost effectiveness are in question. PCR could provide an alternative for laboratory diagnosis of trichomoniasis by culture.
Radonjic
Ivana V
IV
Department of Clinical Parasitology and Immunology, Institute of Microbiology and Immunology, University of Belgrade Faculty of Medicine, Dr. Subotica 1, 11000 Belgrade, Serbia and Montenegro. medparbg@eunet.yu
Dzamic
Aleksandar M
AM
Mitrovic
Sanja M
SM
Arsic Arsenijevic
Valentina S
VS
Popadic
Dusan M
DM
Kranjcic Zec
Ivana F
IF
D000328:Adult; D000818:Animals; D005260:Female; D006801:Humans; D008853:Microscopy / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods; D014245:Trichomonas Infections / Q000175:diagnosis*; D014246:Trichomonas vaginalis / Q000302:isolation & purification* / Q000382:microbiology