Screening for urinary albumin/creatinine The prevalence of diabetes mellitus has been increasing every year in recent years, and patients are often combined with hypertension, hyperlipidemia and hyperuricemia, which together with hyperglycemia damage the kidneys. The earliest manifestation of diabetic kidney damage is the presence of microalbumin in the urine. Therefore, after excluding other factors causing nephropathy. Urine albumin/creatinine can be measured to know the extent of kidney damage. Diagnostic criteria for diabetic nephropathy: The main criteria are a history of diabetes mellitus combined with diabetic fundus changes and an increase in urinary microalbumin excretion rate (i.e., urinary microalbumin/creatinine) (normal <20 μg/min and <30 mg/24h). The diagnosis requires 2 consecutive urine tests within 6 months with a microalbumin excretion rate >20 μg/min but between 30 and 300 mg/24h, while other possible causes of its increase, such as urinary tract infection, exercise, primary hypertension, heart failure and increased water load, should be excluded. If the urinary albumin excretion is still 20-200 μg/min when diabetes is effectively controlled, it can be considered to have early diabetic nephropathy.