The goal of this study is 1. to improve the accuracy of chlamydia multi-site testing in men who have sex with men (MSM) and trans-women, whilst saving diagnostic costs, by comparing two new pooling methods with the 3-samples tested separately 2. to assess the diagnostic accuracy of pooled specimens for lymphogranuloma venereum detection (LGV) - a type of chlamydia infection Chlamydia and gonorrhoea testing for MSM and trans-women usually involves 3 samples from the throat, bum and wee-pipe. The tests can be combined into a single sample pot (pooled sample) which reduces costs, but in a previous study this reduced the accuracy for finding chlamydia. The main question for this study is: Can the accuracy of chlamydia testing in a pooled sample be improved by reducing the amount of urine added to minimise dilution, or by using a meatal sample instead of a urine sample? Participants will be asked to complete two sets of their own throat and bum samples, and then combine these into two pooled samples with 1)a meatal swab and 2)a smaller amount of first catch urine. The order of these samples will be randomised. These samples will be compared against separate samples taken at the same visit, to see how accurate the pooled samples are at diagnosing chlamydia and gonorrhoea with the different sampling techniques.