If you are experiencing symptoms like swelling in your feet and ankles, high blood pressure, or fatigue, your doctor may recommend renal function tests to assess the health of your kidneys. The kidneys play a critical role in filtering waste products and excess fluid from the blood, so it’s important to keep them functioning properly.

In this blog post, we will discuss the purpose, types, and procedure of Renal Function Tests. We will also provide useful information on how to prepare for these tests and what to expect during and after the procedure.

Purpose of Renal Function Tests

Renal function tests are a series of laboratory tests that are used to evaluate the kidneys’ ability to filter waste products and excess fluids from the blood. These tests can help detect and monitor kidney disease, assess the effectiveness of treatment, and identify any potential complications.

Types of Renal Function Tests

There are several types of renal function tests that can be performed, including:

Blood Urea Nitrogen (BUN) Test:

This test measures the amount of nitrogen in your blood that comes from urea. Urea is a waste product produced by the liver, which is eliminated from the body through the kidneys. An elevated BUN level may indicate a problem with the kidneys.

Creatinine Test:

This test measures the level of creatinine in the blood. Creatinine is a waste product produced by muscles and eliminated from the body through the kidneys. High creatinine levels may indicate kidney dysfunction.

Glomerular Filtration Rate (GFR) Test:

This test measures how much blood passes through the glomeruli, tiny filters in the kidneys, every minute. A low GFR rate may indicate decreased kidney function.


This test evaluates the urine for the presence of abnormal levels of protein, blood, or sugar, which may indicate kidney damage.

Procedure for Renal Function Tests

To perform renal function tests, a small amount of blood and urine samples are collected. Blood samples are usually collected from a vein in the arm, while urine samples are collected in a sterile container.

Before the test, your doctor may advise you to avoid certain medications or foods that can affect the test results. You may also be asked to fast for a certain period before the test.

During the procedure, you will be asked to provide a blood and urine sample, which will be sent to a laboratory for analysis. Typically, the test results are available in a few days.


Renal function tests are a valuable tool in diagnosing and monitoring kidney disease. By understanding the purpose, types, and procedure of these tests, you can be better prepared for what to expect during the procedure. If you are experiencing symptoms that may indicate kidney problems, talk to your doctor about getting a renal function test.