In principle, it is better to retain urine from the first urination in the morning for routine urine tests. This is because the concentration of solutes in the urine is higher at this time, which makes it more likely to detect potential diseases. It is also better to take urine from the time when the patient’s urinary symptoms are most severe, such as when the pain of urination is more obvious, or when there is cloudy urine, or when there is bleeding in urination, and the results are more accurate. Urine from other times is less likely to detect underlying diseases than the above, so it is better to retain urine from the first urination in the morning or when the symptoms are most severe, if possible. At the same time, it is recommended that urine be sent to the laboratory within half an hour after it has been collected, so that it does not take too long to grow bacteria or deteriorate, leading to inaccurate test results.