Kidney Function Test: Key Information

The kidneys play a vital role in maintaining health by filtering the blood of waste and eliminating it as urine. They also help regulate levels of essential bodily fluids and minerals.  In this article, we will explain everything related to the kidney function test that a doctor may request to assess the efficiency of kidney function. 

What is Meant by Kidney Function Test?

The kidney function test is a set of blood and urine tests ordered by a doctor to assess the efficiency of kidney function. Most of these tests verify the kidneys' efficiency in removing waste from the body by measuring the Glomerular Filtration Rate (GFR). 

When is the Kidney Function Test Performed?

A doctor usually requests a kidney function test:

1. To monitor conditions or diseases affecting the efficiency of kidney function, such as diabetes and high blood pressure.
2. When symptoms indicating potential kidney problems appear, such as blood in the urine, pain during urination, frequent urination, or difficulties initiating urination.

What are the types of Kidney Function Tests?

Kidney function tests vary, and a doctor may request one or more of them. Here is an explanation of the main tests a doctor may order to assess kidney function:

• Blood Tests

The key blood tests a doctor may request to evaluate kidney function include:

1. Blood Urea Nitrogen (BUN)

Blood urea nitrogen (BUN) is a waste product present in the blood, which the body eliminates through the kidneys.

BUN is produced from the breakdown of proteins in the foods a person consumes, and its normal levels vary from one individual to another based on age and health status. The normal range in the blood is typically between 7 - 20, and higher levels may indicate poor kidney function.

Physicians usually request this kidney function analysis and other tests to assess kidney health. 

Blazma offers a Urea-Serum analysis that requires no prior preparation.

2. Serum Creatinine

Creatinine is a waste product found in the blood, resulting from the natural breakdown of muscle tissues. The body eliminates creatinine through the kidneys.

The normal level of creatinine in the blood depends on age, gender, body size, and other factors. Elevated levels, typically above 1.2 for women and 1.4 for men, may indicate acute kidney injury or chronic kidney disease.

Blazma provides a Creatinine-Serum analysis to evaluate kidney efficiency in performing its functions.

3. Estimated Glomerular Filtration Rate (eGFR)

eGFR is an estimated numerical value based on age, gender, ethnicity, height, and weight. It helps the physician assess the kidneys' efficiency in removing waste from the blood.

An eGFR below 60 indicates suboptimal kidney function and a value below 15 suggests kidney failure. While a reliable test for assessing kidney function, it may be less accurate in individuals under 18, pregnant women, or those with significant weight gain.

Blazma offers an Estimated glomerular filtration rate analysis, which requires fasting and discontinuation of specific medications, and abstaining from meat consumption the night before the examination.

• Urinary Tests

Kidney function can be analyzed by examining a urine sample, and the following are the key tests:

1. Urinalysis

During a urinalysis, a sample of urine is examined for proteins and blood. Initially, a visual examination is conducted to check the sample's color and clarity. Subsequently, a strip is immersed in the urine sample capable of determining whether there is a significant amount of protein, blood, sugar, acids, or bacteria. Finally, the sample may be examined under a microscope. 

Physicians typically request the test on a urine sample collected over 24 hours.

Blazma provides a range of urine tests, including: a Creatinine-24 hrs urine analysis, a Total protein-24 hrs Urine analysis, a total Protein-Urine analysis, and a Creatinine clearance-24 hrs Urine analysis.

2. Urine Albumin-Creatinine Ratio (uACR)

In this test, the quantity of albumin and creatinine in the urine is measured, and then the amount of albumin is divided by creatinine. A ratio of less than 30 milligrams/gram is considered normal.

It is worth noting that under normal circumstances, when the kidneys are healthy, albumin should be maintained in the blood, and creatinine should be filtered into the urine. Therefore, there should be no albumin in the urine at all, or only a very small amount. 

Blazma provides this analysis under the name of the urinary Albumin/Creatinine ratio.

How Are Kidney Function Tests Conducted?

Kidney function tests require either collecting a 24-hour urine sample or providing a blood sample for analysis. Here are some details on how to collect these samples: 

• Collecting a Urine Sample

To collect a 24-hour urine sample, you must follow the following instructions:

1. Urinate in the toilet after waking up for the first time.
2. Throughout the day, collect urine in a designated container and securely seal it before placing it in the refrigerator.
3. Urinate into the same container upon waking up for the first time on the second day to complete the 24-hour collection.
4. Deliver the sample to the laboratory.
   

• Blood Sample

A technician uses a small needle and a test tube to collect a blood sample for analysis. This analysis does not require any prior preparations.