What is the Creatinine Clearance?
Creatinine clearance is the means of measuring the rate of creatinine filtration from the bloodstream through the kidneys. Creatinine is a metabolite of creatine, which is a muscle protein that is involved in the production of energy during muscular contraction. In its normal state, creatinine is filtered through the kidneys and excreted in the urine. The Creatinine Clearance test is a good marker of kidney function, more specifically the glomerular filtration rate (GFR), which is a measure of the kidney’s filtering ability.
The test is used in identifying kidney function disorders including CKD or AKI. The creatinine clearance value is derived from the creatinine level in the blood, urinary creatinine level, and the volume of urine passed within a given time.
How is the Test Performed?
For the test, two major things are required, blood and urine samples. Sometimes, the blood sample is drawn to determine serum creatinine level while the urine sample is obtained over a period of 24 hours. The 24-hour collection is generally employed to guarantee correct urine creatinine concentration.
When both samples are received, they are then sent to the laboratory to determine the creatinine clearance rate which is in mL/min. The formula used to estimate the clearance is based on the relationship between the creatinine concentrations in the serum and urine and the patient’s weight, age, and gender.
The patients are told some guidelines on what to do during the 24-hour urine output test to get accurate results. It is also advised that the patient should not engage in any strenuous exercise since this may raise the creatinine level and there are some foods and medications that the patient should avoid as told by the doctor.
What are the symptoms that prompt this test?
Your healthcare provider may order a Creatinine Clearance test if you have symptoms or other indicators of kidney failure.
General Symptoms
- Fatigue
- Edema
- Shortness of breath
- Appetite loss
- Bloody, foamy urine
- Frequent urination
- Persistent hypertension
What are Normal Ranges for This Test?
It is important to understand that the normal creatinine clearance values can vary depending on the laboratory methods used and the manner in which the calculation has been done. Additionally, the results can be affected by the patient’s hydration status, muscle mass, and diet.
Male – 97 to 137 mL/min
Female – 88 to 128 mL/min
**Various other factors like age, gender, and muscular composition of the individual also have some impact on the values obtained. The results of the test should always be used in conjunction with other clinical information in order to establish a diagnosis.**
What Happens if Test Results Show Abnormal Levels?
Abnormal levels indicate that the kidneys are not functioning effectively and may require further testing. The following could be the possibilities of inefficiency;
- Chronic kidney disease
- Acute kidney injury
- Glomerulonephritis
- Obstruction
If abnormalities are diagnosed further testing is suggested along with medications and lifestyle modifications.
