Renal function tests include creatinine, urea nitrogen and uric acid. Generally speaking, renal function test is a blood test, and generally require fasting blood test, that is to say, in the morning of the blood test can not eat. It is recommended to have a light diet within three days before the blood test, avoiding large meat food, which may affect the test results. And if you have not had a good rest in the last few days, there is also a possibility that the test results will be affected. If the blood creatinine and urea nitrogen are elevated, it is often suggestive of renal insufficiency, and it is necessary to go to the hospital in time to clarify the cause of renal failure. In addition, increased uric acid is often seen as a result of decreased glomerular excretion rate or eating too much food containing purines. Therefore, if you have increased uric acid, you should avoid eating foods that are too high in purines such as animal offal and seafood.