The current laboratory test to investigate for a bacterial UTI involves providing a fresh urine sample. This is known as a mid-stream urine culture or MSU. To get an accurate result and avoid bacterial contamination, a “clean” midstream urine sample is used. This means you don’t collect the first or last part of the urine stream but only the middle part by interrupting the flow of urine after a few seconds and then collecting this middle part of the urine flow in the sample bottle provided. Once collected, the sample is sent by your GP or consultant to the laboratory for analysis.