24-hour urine creatinine

Creatinine mainly refers to the metabolite produced by human muscles during the human body's circulation. It is mainly divided into endogenous creatinine and exogenous creatinine. When patients have gastrointestinal or digestive system problems and go to the hospital for treatment, many doctors will recommend that patients undergo a urine test first. The urine test index can show the patient's 24-hour urine creatinine index. So what does 24-hour urine creatinine mean?

Urine creatinine (Cr) refers to the concentration of creatinine in urine measured over a 24-hour period. Creatinine is a product of human muscle metabolism, including both exogenous and endogenous sources. Exogenous creatinine is the product of meat metabolism in the body; endogenous creatinine is the product of muscle tissue metabolism in the body. Creatinine is mainly excreted from the body through glomerular filtration and is no longer reabsorbed. The variation of urine creatinine concentration is related to daily diet. The excretion of creatinine varies greatly within a day, so the determination of urine creatinine requires the collection of all urine for 24 hours. The 24-hour urine creatinine measurement will be interfered by many factors, such as being placed for 24 hours, improper collection method, environmental factors, etc.

Normal reference range

The normal reference value of urine creatinine is 8.4~13.2mmol/24h (94.9~149.2mg/24h).

Clinical significance

24-hour urine creatinine can assist in the diagnosis of many clinical diseases. For example, the urine protein-creatinine ratio can help diagnose early diabetic renal damage; the ratio of urine amylase to urine creatinine can assist in the diagnosis of acute pancreatitis; the simultaneous detection of 24-hour urine creatinine and blood creatinine can calculate the 24-hour creatinine clearance rate. Creatinine clearance is one of the main indicators used clinically to evaluate glomerular filtration rate, providing a scientific basis for the diagnosis, detection and prognosis of acute and chronic kidney disease.

1. Increase: diseases that cause excessive creatinine production in the body, such as acromegaly, gigantism, diabetes, infection, hypothyroidism, etc.

2. Reduce: renal failure, severe congestive heart failure, etc.

In addition, eating meat, strenuous exercise, taking vitamin C, levodopa, methyldopa, etc. can increase urine creatinine; vegetarians, taking androgens, and thiazide drugs can reduce urine creatinine test results.

Urine creatinine measurement precautions

1. Before the examination: avoid strenuous exercise, maintain a good diet and work and rest schedule, stop taking medications that may cause changes in urine chlorine levels one week before the examination, and avoid drinking alcohol 3 days before the examination.

2. All urine collected over 24 hours should be stored at 2-4°C.

3. The urine sample should not be left for too long.

4. Women who are menstruating or those who have a cold are not suitable for urine creatinine testing.