Kidneys are a pair of bean-shaped organs situated in the abdomen. They play several important roles in our body and are their optimal functioning is important for our health and well-being.
Functions of Kidneys
Kidneys have the following functions in our body:
- Eliminate body wastes
- Remove extra water from the blood (as urine)
- Release hormones that regulate blood pressure
- Control the production of red blood cells (RBCs)
- Produce an active form of vitamin D that makes the bones strong and healthy
Renal function test
Kidney or renal function test, also called renal profile test or kidney profile tests, is done to determine if your kidneys are functioning well. These tests mostly comprise of a blood test, 24-hour urine sample or both. Since kidneys remove toxins, wastes, and extra fluid from the blood, a blood test can indicate whether the kidney is functioning well. On the other hand, urine test is done for the early detection of kidney disease as damaged kidneys will result in protein leakage in the urine (proteinuria).
Most tests usually measure the glomerular filtration rate (GFR) which indicates how efficiently the kidneys are working towards waste removal from the body.
Why to get a kidney test?
Chronic kidney disease (CKD) is a serious condition affecting the kidneys. In CKD, the kidneys get damaged to such an extent that they are unable to filter waste from the blood. CKD is more commonly seen in diabetic patients where the kidneys are silently damaged without any evident symptoms.
In order to detect and treat kidney disease at an early stage, it is important to undergo kidney/renal function test. It will keep the CKD from getting worse and also protect from other health issues such as heart disease.
KFT test list
Broadly, a kidney function test includes the following tests:
- Blood urea/blood urea nitrogen (BUN)
- Serum creatinine
- Estimated glomerular filtration rate (eGFR)
- Microalbuminuria
- Dipstick urine test
- Urine albumin-to-creatinine ratio (UACR)
Kidney profile test
A. Blood tests- Blood tests included in the renal function test are:
1. Blood Urea/Blood Urea Nitrogen (BUN): It is a measure of the amount of urea nitrogen in the blood, which is a waste product from protein metabolism. A healthy kidney filters out urea nitrogen from the body through urine, keeping the BUN level within a normal range of 7-20. A higher level of BUN indicates kidney damage.
2. Serum creatinine: This test measures the level of creatinine in the blood. If the kidneys are not functioning well, serum creatinine levels go up. Normal creatinine values are affected by age, sex, and muscle mass of the body. Creatinine values within 1.1 for females and 1.3 for males are generally considered normal. Values higher than these indicate improper functioning of the kidneys.
3. Estimated Glomerular Filtration Rate (eGFR): GFR value shows how well the kidneys are functioning in order to remove wastes, toxins, and extra fluid from the blood. For calculating the GFR number, serum creatinine value is also measured. A low GFR indicates that the kidneys are not working normally. A GFR is about the same as your percent kidney function. For example, a GFR of 58 means that you have a kidney function of 58%. In cases like CKD, the value of GFR goes further down. The values for this kidney function test result is interpreted as follows:
• A GFR number of 90, along with normal urine albumin test, shows a normal range.
• GFR number less than 60 indicates a kidney disease. If this value dips below 15, it is a sign of kidney failure. Such a person may be required to go in for a dialysis or kidney transplant. A kidney transplant is generally needed if the GFR value is constantly below 20 over a period of 6-12 months.
B. Urine tests- Urine test for kidney function includes these tests:
1. Microalbuminuria: This is a 24-hour urine test to check for a specific protein called albumin in the urine sample. The normal level should be less than 30mg.
2. Dipstick urine test: This test is part of the overall urinalysis but can be done just to measure if the albumin levels are normal. However, it does not give the exact measurement of albumin. A dipstick is a chemically treated paper which changes color if the urine sample provided has elevated levels of albumin.
3. Urine albumin-to-creatinine ratio (UACR): This test measures and compares the amount of albumin with the amount of creatinine in the urine. With the help of this test, your health care practitioner can know how much albumin passes in your urine during 24 hours. UACR value of 30 or above indicates kidney disorder.
DTPA Kidney Test
A renal DTPA scan is done to diagnose and evaluate if the kidneys are functioning properly. In this scan, a radiopharmaceutical material, diethylenetriamine pentaacetate (DTPA) is introduced intravenously to study and assess the drainage pattern of kidneys and detect if any part of the organ is not functioning effectively. The images are captured using a special gamma camera. The DTPA scan is mainly done to measure the glomerular filtration rate (GFR). It can be performed along with a GFR blood test.
Kidneys play a very important role in waste and toxin elimination from the body. It is therefore, advisable to opt for renal function test, especially if you are a diabetic. Timely detection and proper intervention can prolong the life of your kidneys by undergoing a kidney function test. Protect your kidneys from developing serious diseases like chronic kidney disease by going for regular blood and urine tests as part of your renal profile test. Let’s join hands to beat CKD and move towards leading a healthy life!
