The proportion of clinically important diagnoses in a low-risk, asymptomatic population who use a computer-assisted self-interview (CASI) to assess risk was needed to determine optimal health service delivery. Medical records were retrospectively analysed between July 2008 and June 2009 for risk characteristics and diagnoses. A total of 7733 new patients completed a CASI, of whom 1060 were asymptomatic heterosexuals. From this low-risk group, 26 diagnoses were made on the day of presentation, including 22 cases of genital warts (2.08% [95% confidence interval (CI) 1.22-2.93]), three cases of genital herpes (0.28% [95% CI 0.055-0.82]) and one case of unintended pregnancy (0.094% [95% CI 0.0061-0.52]). Additionally, there were 54 cases of chlamydia detected (5.09% [95% CI 3.77-6.42]). As chlamydia is effectively diagnosed and managed from self-collected samples, patient review is not always required. This study provides evidence for an express testing service for chlamydia to streamline the screening of low-risk, asymptomatic heterosexual patients as identified by CASI without the need to for a traditional face-to-face consultation.