Kidney Function Tests

Kidney Function Tests
Kidney function tests are a collection of tests used to determine the working efficiency of kidneys. Kidneys are some of the important organs of the body and play one of the important roles in maintaining the health of human beings. The most significant function of the kidneys is to filter waste materials from the body and excrete them in the form of urine.

What size is a kidney? The size of the kidneys is measured mainly sonographically, although both CT and MRI scans can be used to estimate the sizes of kidneys. The average length pole to pole of an adult human kidney is considered to determine the size of your kidney.

Different types of kidney function tests are as follows.

Blood Urea Nitrogen (BUN) test
BUN stands for blood urea nitrogen. When protein breakdown occurs, urea nitrogen is formed. A healthcare professional may recommend BUN test to estimate the amount of urea nitrogen in the blood of an individual.

Read Also: Why do Kidney Stones occur?

A blood sample is required to carry out this test. Mostly, blood is drawn from a vein situated on the inside of the elbow or the back of the hand.

Creatinine blood test
The creatinine (a waste product from the normal breakdown of muscle tissue) blood test is performed to evaluate the level of creatinine in the blood and to see how efficiently the kidneys are functioning. Creatinine levels can also be estimated with a urine test. To perform this test a blood sample is needed. If the levels of creatinine are found higher an appropriate treatment is provided. Dialysis is a treatment that filters and purifies the blood using a machine and is recommended when other treatments are not working. Dialysis side effects are considered before switching from other treatments to dialysis.

Creatinine clearance test
The creatinine clearance test helps provide information about how effectively kidneys are functioning. This test is performed to compare the creatinine level in urine with the creatinine level in blood. To perform this test, both a urine sample and a blood sample are required.

Creatinine urine test
The creatinine urine test is used to determine the amount of creatinine in urine. This test helps to determine the proper functioning of the kidneys. Creatinine can also be estimated by a blood test.

Once a urine sample is taken, it is tested in the lab to estimate creatinine levels. A healthcare professional may ask to collect urine at regular intervals over 24 hours if required. Follow the instructions given by the doctor exactly so that the results are correct.

Glomerular filtration rate (GFR)
GFR test is used to determine how efficiently the kidneys are filtering waste. The test determines the glomerular filtration rate by considering various factors including test results (especially look for creatinine levels), gender, race, age, height, and weight.

How to prepare for these tests?

• The test may need a 24-hour blood test and/or a urine sample.
• For the purpose of collection of the urine sample, a special container is provided in which urine can be collected directly at regular intervals over a period of 24 hours.
• After collecting the urine sample, make sure that you cover the lid of the container, label and keep it in the refrigerator.
• For the blood test, no other special container is required.

When is the kidney function test performed?
The kidney function test is recommended by healthcare professionals when an individual suffers from any kidney malfunctioning or people come up with symptoms such as:

• an elevated blood pressure
• blood in urine
• Frequent urination
• inflammation in the hands and feet
• trouble to pass urine
• discomfort and painful urination

Read Also: Risk Factors for Chronic Kidney Disease

If you notice any of the above symptoms that may be indicative of some kidney problem, you should immediately contact your healthcare provider so that he or she may perform necessary tests to determine the actual cause of the problem and understand if it is due to some kidney problem in the body.