Know Everything about Common Kidney Function Tests

You have two kidneys, one on each side of your spine, each about the size of a human fist. They are behind your abdomen and underneath your ribcage.

The kidneys perform numerous crucial tasks for sustaining good health. Filtering waste and removing it from the body as urine is one of their most crucial functions. The kidneys also manage the levels of vital minerals and water in the body. They are also essential for synthesizing red blood cells, vitamin D, and blood pressure-regulating hormones.

You may need kidney function tests if your doctor suspects your kidneys aren’t functioning properly. These simple blood and urine tests help diagnose any problem with your kidneys.

Types of kidney function tests

Your doctor will give you a series of tests for kidneys to determine your glomerular filtration rate (GFR) and assess the health of your kidneys. The GFR measures how quickly your kidneys are removing waste from your body.


A urinalysis checks the urine for the presence of blood and protein. Protein in urine can occur for various reasons, not all of which are medical. Both infection and strenuous physical exertion can cause an increase in urine protein. After a few weeks, your doctor can conduct this test again to verify that the outcomes are consistent.

You might also be asked to give your doctor a 24-hour urine collection sample. This enables medical professionals to monitor the rate at which a waste substance called creatinine leaves your body. Muscle tissue breaks down into creatinine.

Blood urea nitrogen (BUN)

The blood urea nitrogen (BUN) test also examines your blood’s waste levels. BUN tests evaluate the blood’s nitrogen content. Nitrogen urea is a result of protein degradation. However, not all elevated BUN levels signify kidney damage. 

If you take a lot of prescription medications, such as some antibiotics and high aspirin dosages, your BUN may also rise. It’s important to inform your doctor of any vitamins or medications you take regularly. You might need to stop using some medications a few days before the test.

How The Tests Are Performed

Tests for kidney function require a blood test and a 24-hour urine sample.

24-hour urine sample

A 24-hour urine sample is required for a creatinine clearance test. Your doctor gets an idea of the daily creatinine output from the body. Use the restroom as you normally would when you wake up and begin the test. Use the special container your doctor provided to urinate into for the rest of the day and night. 

Blood samples 

Blood samples must be drawn in a lab or doctor’s office for BUN and serum creatinine tests. Before drawing blood, the technician secures an elastic band around your upper arm. This highlights the veins. It penetrates your skin with a hollow needle and again into the vein. Once more, the blood will flow into a test tube for analysis.

Parting Words

If the tests reveal early kidney damage, your doctor will concentrate on treating the underlying illness. If the kidney testreveals hypertension, your doctor will prescribe medicines to lower blood pressure. They’ll also recommend lifestyle and dietary changes. Dr. Lal Pathlabs has years of expertise and a competitive kidney function test price to help you deal with your kidney problems.

Your doctor will take the necessary steps to treat any illnesses that may be the cause of your abnormal kidney function tests, like kidney stones and excessive painkiller use. A kidney stone test is prescribed to identify the occurrence of kidney stones.

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1. What is the normal BUN level?

Between 7 to 20 mg/dL is considered a normal BUN level.

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