In normal renal function, creatinine-height index is a biochemical index to determine the amount of muscle protein consumed. Creatinine is a metabolite of creatine (creatine is mostly found in muscle tissue and contains about 400~500mg of creatine per 100g of muscle), and its excretion is closely related to total muscle mass, body surface area and body weight, and is not affected by fluid infusion or fluid retention, and is more sensitive than indicators such as nitrogen balance and plasma albumin. In protein malnutrition, wasting disease and muscle wasting, creatinine production decreases and so does urinary excretion. Under normal conditions, the 24-hour creatinine excretion in healthy adults is about 23
mg/kg body weight (men) and 18 mg/kg body weight (women).
Measurement method: The 24-hour urine is accurately collected from the patient, analyzed for creatinine excretion, and compared with the urinary creatinine excretion of a healthy person of the same height to measure the degree of skeletal muscle deficit by the creatinine-height index. Creatinine excretion is reduced in renal failure.
Creatinine-height index = 24-hour urinary creatinine excretion (mg) divided by 24-hour urinary creatinine excretion (mg) of a healthy person of the same height. Evaluation criteria: The creatinine-height index number of a patient compared with that of a healthy adult, 90% to 110% is considered normal nutrition, 80% to 90% is considered mild malnutrition, 60% to 80% is considered moderate malnutrition, and less than 60% is considered severe Malnutrition.