Nephritis tests are best done on an empty stomach. If nephritis is not diagnosed, but only suspected, you need to do the appropriate comprehensive examination. At this time, blood needs to be drawn for kidney function, and if eating will have an effect on the kidney function test, so it is best to have the test on an empty stomach. It is also better to fast for other tests, because eating may cause celiac blood and affect the blood test. If you want to review the urine routine or 24h protein quantification, you don’t need to fast, but if you need to take blood for kidney function, you need to fast too. In addition to fasting, it is best not to throw away the first urine in the morning and use this urine for routine urine examination will be more accurate.