Urine tests should not be done during menstruation because the urine specimens that are retained are often substandard and there is a possibility that menstrual blood will flow into the urine. The results of routine urine tests will then show a large number of red blood cells, which can have a very serious adverse effect on the urine test and there is a risk of misdiagnosis. There is no way to determine whether the menstrual blood is the cause or the cause of the disease, so that the test results are not available as a basis for disease diagnosis. Therefore, it is best not to perform urine tests during menstruation, as many results are meaningless. If there are no special circumstances, it is recommended to do the urine routine test after three days of menstruation, which will be more accurate, and be sure to discard the first part of the urine and take the middle urine. However, if symptoms of acute urinary tract infections such as frequent, urgent and painful urination occur during menstruation, the test can also be done. However, it is best to block up the vaginal opening with paper to avoid menstrual blood from flowing into the urine when receiving urine.