Also referred to as renal function test (RFT), a kidney function test (KFT) is a urine or blood examination that assesses the functionality of your kidneys. Situated in the back of your abdomen and below your ribcage, the two kidneys are vital components of the urinary system. Their primary function is to filter waste materials from your body and eliminate them as urine. KFTs evaluate the efficiency of your kidneys in clearing waste from your system. Read on to learn all about what a Renal Function Test (RFT) test involves.

Why is a KFT prescribed?

Conditions such as diabetes (high blood sugar levels) and hypertension (high blood pressure) significantly affect kidney function. Individuals with these conditions may undergo kidney function tests prescribed by their doctors to monitor their progress. Likewise, if someone exhibits symptoms suggestive of kidney problems, they may also require an RFT test. These symptoms include:

• Fluid retention in the body leading to swelling of the hands and feet
• Presence of blood in the urine
• Increasing blood pressure
• Difficulty urinating
• Frequent urination
• Pain during urination

What Does a KFT Include?

An RFT test comprises several evaluations that may vary from one laboratory to another or based on the doctor’s specific requests. However, common components tested in most renal panels typically include:

• Blood Urea/Blood Urea Nitrogen (BUN): Derived from blood urea, this test measures waste products generated by protein metabolism, which the kidneys filter and eliminate in urine.

• Calcium: Essential for muscle, cardiovascular, bone, and nervous system health, calcium levels are regulated by kidneys. Elevated levels may indicate increased kidney workload.

• Creatinine: It is a byproduct of muscle metabolism. Kidneys filter creatinine from the blood for excretion in urine, making it a marker of kidney function.

• Phosphorus: It is crucial for teeth, nerve, bone, and muscle health. It plays an important role in various bodily functions and is obtained from dietary sources.

• Sodium: It is an electrolyte vital for maintaining fluid balance and nerve function. Kidneys help regulate sodium levels in the body.

• Uric Acid: This test analyses a nitrogenous compound produced from purine metabolism. Elevated levels may indicate issues with kidney function or metabolic disorders.

• Chloride: An electrolyte, chloride works with other electrolytes to maintain fluid balance, acid-base balance, and nerve function. It is obtained from dietary sources and regulated by kidneys.

• Potassium: Essential for muscle function, nerve transmission, and maintaining fluid balance, potassium levels are regulated by kidneys. Imbalances can affect heart rhythm and other bodily functions.

Types of Kidney Functions Tests Available

Your healthcare provider may order various types of kidney function tests, including blood and urine tests. Blood tests may include:

• Blood Urea Nitrogen (BUN): This test measures nitrogen levels derived from protein breakdown in your blood.

• Serum Creatinine: This test detects the accumulation of creatinine, a waste product from muscle tissue breakdown, in your blood.

• Estimated Glomerular Filtration Rate (eGFR): It calculates kidney filtration rates based on factors such as protein levels, age, gender, size, and race.

Urine tests may include:

• Urinalysis: It evaluates the urine sample for the presence of blood, proteins, and overall kidney function.

• Microalbuminuria: This test detects the presence of a specific protein called albumin in the urine sample.

A kidney function test, also known as RFT test, assesses the efficiency of your kidneys. Healthy kidneys play a vital role in eliminating waste from your body. Conditions like diabetes or high blood pressure can impact kidney function. Additionally, kidney function tests can help diagnose or exclude infections. These tests involve either blood or urine analysis. Usually, your healthcare provider shares the results on the same day or within a few days.