What is a 24-hour Urinary Creatinine Test?
Creatinine is a natural byproduct formed by the muscle activity. It is filtered by kidneys and excreted from the body through urine. Measurement of creatinine levels provide an essential insight about kidney health, muscle metabolism and monitoring chronic conditions including chronic kidney disease (CKD).
The 24-hour urinary creatinine test evaluates the amount of creatinine excreted in urine throughout the day. It is usually performed with other tests for the diagnosis of conditions affecting kidney health and muscle integrity.
How is the Test Performed?
The 24-hour urinary creatinine test is a noninvasive procedure involving collection of urine over a 24-hour period. Collecting the urine accurately is important to ensure valid results. Your doctor might ask you to not eat meat before and during the test.
Collection
On the first day, discard the first urine and note that time. From that point, start collecting the urine throughout the day in a special container provided by the laboratory. Include the urine of the next morning in the container as well.
Storage and Handling
The sample must be stored in a cool place like a refrigerator during the collection period to avoid contamination and degradation of the sample.
Submission
The container should be returned to the lab as instructed.
Lab analysis
After sample collection the sample is analyzed in the laboratory using advanced techniques like High performance liquid chromatography (HPLC), enzymatic method and others depending on the laboratory.
What are the symptoms that prompt this test?
Your healthcare provider may suggest this test when you show signs of poor kidney function, abnormal muscle metabolism, and other related conditions
General symptoms
- Persistent fatigue and weakness
- Swelling in hands, feet, and face (edema)
- Changes in urine volume and frequency
- High blood pressure that does not respond to the treatment.
- Changes in skin appearance as it may appear dry, itchy, yellowish, or pale. It might also thicken and develop cysts and bumps.
- Bad taste in the mouth
- Twitching muscles
Specific conditions
- Kidney diseases such as chronic kidney disease or acute kidney injury
- A condition called rhabdomyolysis where excessive muscle breakdown causes increased levels of creatinine
- Kidney health of patients with diabetes, hypertension, or autoimmune disorders.
What are Normal Ranges for This Test?
The results depend upon the age and lean body mass of an individual. Normal ranges for urinary creatinine are 500-2000 mg/day generally.
Adult Males – 14 to 26 mg/day per kg body mass
Adult Females – 11-20 mg/day per kg body mass
**These values are general guidelines and vary according to the assay of the test, patient-specific factors, and diagnostic findings.**
What Happens if Test Results Show Abnormal Levels?
Normal creatinine levels ensure that the kidney is functioning properly and the body is healthy. Abnormal creatinine levels indicate various conditions that are listed below;
- High Creatinine Levels indicate
- Increased muscle activity or muscle mass
- Certain kidney disorders including diabetic kidney, kidney failure, or kidney infection
- High protein diet
- Low Creatinine Levels indicate
- Low muscle mass
- Poor kidney function
- Over-hydration
- Obstruction in the urinary system
If abnormalities are diagnosed further testing is suggested including blood creatinine level, kidney biopsies, and imaging studies to identify underlying causes.
