The human body has two bean-shaped organs right at the lower back portion above the pelvic girdle. This pair of organs is responsible for the filtration of blood by removing the by-products of cellular metabolism and other physiological functions. Both kidneys together produce 1 to 1.5 litres of urine every day by filtering at least 200 litres of blood.

A routine check-up of the functioning of kidneys becomes mandatory at a particular age. The biggest issue of kidney diseases is that the symptoms do not surface anytime soon unless the situation has become worse. Moreover, individuals are also unaware of the symptoms that indicate kidney ailments. This is why a comprehensive set of clinical tests is designed to detect such anomalous developments.

Types of kidney function tests

A kidney function test (KFT test) is designed based on the measurement of a particular type of metabolite or by-product present in the urine or bloodstream of the human body. The normal range of various metabolites and by-products has been defined so that the test results can be interpreted well for the diagnosis of underlying issues (if any). Here is the list of kidney function tests we should know about.

1. Urinalysis

This is a screening process that checks the presence of blood and protein in the urine. A sample is collected from the individuals to check the levels of protein. Not all kinds of protein present in the urine sample are harmful.

The presence of protein in the urine samples can lead to the diagnosis of infections and heavy workouts. This test is generally repeated after a few weeks for monitoring the levels. A 24-hour urine collection process is also conducted to check the level of creatinine in the urine produced.

• Serum creatinine test

 It is a blood test where the clinical experts check whether creatinine is building in your bloodstream or not. The prime reason behind checking the level of this compound is that kidneys continuously filter creatinine from the system. Hence, the level of creatinine will determine the proficiency of a person’s kidneys. A higher level, thus, will depict the abnormal functioning of kidneys. The range of creatinine higher than 1.4 mg/dl in men and 1.2 mg/dl in women depicts kidney issues.

• Blood urea nitrogen (BUN)

This is a blood test that checks the level of waste products present in your bloodstream. BUN test is conducted to measure the level of nitrogen present in blood as urea nitrogen is the metabolite or by-product of protein catabolism.

An elevated test result may or may not conclude kidney problems. The consumption of common antibiotics and painkillers can also cause the BUN level to increase. Hence a doctor asks proper questions to the patients to understand the condition and then prescribes this test. It can be repeated to check whether there is any significant change in the BUN level during or after treatment.

• Glycated haemoglobin test (HbA1c test)

The measurement of glycated haemoglobin (HbA1c) is done by drawing blood samples from a patient. This test is conducted to check the level of haemoglobin that has been combined with glucose over a time span of 2 to 3 months.

When the level of HbA1c is higher than normal (5.7% or less) then it can indicate the occurrence of diabetes and kidney diseases. This test is done to diagnose the precursors of blood sugar issues. An abnormal result of the HbA1c test can also indicate the occurrence of anaemia among patients suffering from renal disease.

• Estimated glomerular filtration rate (GFR or eGFR)

The filtration takes place in the glomerular part of the nephrons, the structural and functional units of kidneys. The estimated rate of filtration is calculated considering various factors such as:

• Age
• Gender
• Test results of creatinine levels
• Race
• Weight
• Height, etc

The filtration rate depicts how well your kidneys are functioning to remove waste products from your blood. The normal level is 60 ml/min/1.73m². Any level less than this border can depict kidney issues.

Why KFT test is necessary?

As mentioned above, every test is designed to check the specific levels of metabolites and by-products present in the urine or blood samples drawn from an individual. The test results are then compared based on the normal ranges depicted by the medical boards.

The normal range is decided based on the condition of an individual. Once the tests are done, a new level of diagnostic tests is designed if needed to find out the occurrence of any kidney disease beforehand.

The diagnosis of particular issues done by conducting the tests then leads to the design of a treatment procedure. Doctors will prescribe medicines to cure the issues the kidneys are facing. They can also suggest making changes in their lifestyles to get faster and better results.

Wrapping up

We can clearly understand how important these kidney function tests are. All these tests are designed to measure a particular set of compounds present in the urine and blood. Such tests are done by following standard procedures so that the results are accurate. A proper outcome will ensure a faster and better diagnosis of renal disorders.