Uremia in children can be determined mainly by its symptoms and urine test and other auxiliary examinations. 1. Symptoms: It can be manifested as excessive drinking, urination and thirst, and increased nocturia, which affects the children’s sleep and study. Some of the children may also have dry skin, low spirit, poor appetite and weight loss. 2.Auxiliary examination (1) Urine test: increase in urine volume, up to 4-10L per day, decrease in urine specific gravity and decrease in urine osmolality. (2) Water fasting test: dehydration symptoms may appear during water fasting test in uremic children, continuous excretion of hypotonic urine, increase in serum sodium and osmolality, and weight loss of 3%~5%. (3) Pressin test: It is mainly used for differential diagnosis of complete central dysuria, partial dysuria and renal dysuria. If any of the above conditions are present, it is recommended to seek prompt medical attention for diagnosis and treatment.