Fresh urine specimens need to be taken for urine testing. Usually, fresh urine specimens need to be sent within half an hour at room temperature, if more than half an hour, urine evaporation or corruption may occur, and it is recommended to retrieve specimens for testing. However, if the time can be moderately extended in a low temperature state, but needs to be kept at a low temperature of about 4 degrees Celsius, when the urine specimen can be extended to two hours. If more than two hours are exceeded then the urine is considered invalid and additional urine needs to be retained for testing. It is important to avoid contamination of the urine during the process of urine retrieval, and to retrieve as much urine as possible from the middle section for testing, so that the possibility of contamination is relatively small. At the same time, avoid drinking a lot of water or outputting a lot of liquid before urine collection to avoid diluting the urine and causing inaccurate test results.