Kidney Function Test: Everything You Need to Know

Kidney function test

The kidney is one of the vital organs of the body as it filters all the toxins from the body and excretes them in the form of urine. This helps to maintain a good health. It also functions to control the levels of water and other essential minerals in the body. Proper functioning of the kidneys is essential as they help in the production of Vitamin D, red blood cells and hormones that help in regulating the blood pressure level.

If you notice any abnormalities in urine or your body functioning, you must visit a doctor to test the health of your kidney. 

What are the different kidney function tests?

The doctor usually prescribes a series of test to determine the glomerular filtration rate (GFR). The GFR measures the level of kidney function and the severity of the kidney disease. It also tells your doctor if the kidney is at its normal pace in filtering the waste materials from the body. This test guides the doctor on how to administer treatment for kidney problems.

Here are some tests that help the doctor find out the functioning of your kidneys:


This is one of the most common tests prescribed by the doctor to test if there is a presence of blood and protein in your urine. Presence of protein in your urine does not necessarily mean that you have kidney disease. It might happen due to an infection or because of strenuous physical workout. The doctor tells you to collect your urine over 24 hours. By testing this sample, your doctor is able to determine how fast the waste product creatinine is expelled from the body.

Serum creatinine test 

This is a blood test that determines how well the kidneys are getting rid of the creatinine from the body. If the test results in a high level of creatinine, it means that you might have a kidney problem.

Blood Urea Nitrogen (BUN) 

This test measures how much nitrogen is contained in the blood. Urea nitrogen is a breakdown product of protein. However, if the results of the BUN test are elevated, it does not necessarily mean that your kidneys are damaged. It might happen at times due to large doses of aspirin and some antibiotics. Let your doctor know about the medications you are taking and stop them for some days before the test for a correct reading.

GFR test

This is another test that estimates if your kidneys are filtering the waste products well. However, it takes some factors into consideration before determining the rate:

  • Creatinine levels
  • Existing Medical conditions
  • Medications
  • Age
  • Weight
  • Height
  • Gender

How do you know that you need a kidney function test?

These are some symptoms that suggest that you might have a kidney disease. Visit a doctor to know if you need a kidney function test.

  • Chronic exhaustion
  • Feeling cold even if it’s warm
  • Shortness of breath with little work effort
  • Feeling too itchy
  • Fluid retention in hands and feet that cause swelling
  • Puffy face
  • Bad breath that stinks like urine or raw fish
  • Nausea, vomiting, and stomach upset
  • Frequent urge to pee

Be aware of these symptoms and identify them. Visiting a doctor in the early stages of a kidney disease will help in getting treated properly. 

Also, Read:

How to Self-Diagnose If You Have Kidney Stones


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