Trichomoniasis TestWhats Tested Trichomoniasis is a common, curable STI caused by the parasite Trichomonas vaginalis. While women are more likely to get it, both men and women can be asymptomatic, making it easy to spread during sex. It affects the genital and urinary organs and is typically tested using a urine sample or vaginal swab. Left untreated, trichomoniasis can cause complications like infertility, increased HIV risk, and in pregnant women, premature labor.