The first urine after waking up the morning before the examination should be discarded, and all urine from the second urine until the first urine after waking up the morning of the examination should be collected in a large clean container (such as a small bucket of mineral water like Nongfu Mountain Spring), and a preservative should be put into the container (add it at the same time as the first urine, mix it well, and do not add it if the temperature does not exceed 20℃). It is recommended that all urine be sent to the laboratory for examination as soon as possible after the specimen has been retained. In addition: it is recommended not to eat a large meat diet and not to exercise strenuously for 3 days before the specimen is taken. Female patients should avoid the physiological period: if there is a urinary tract infection, etc., it is also not advisable to take urine.