Renal/Kidney Function Test (RFT/KFT): Price, Normal Range

Kidneys are responsible for the excretion of waste products and excess bodily fluids. They also help in the regulation of salts and minerals. Renal function test is a set of tests conducted to assess how efficiently the kidneys perform their function. 

This test helps doctors understand if the kidneys are filtering blood properly and maintaining a healthy balance in the body. It can be done through blood and urine samples. 

Read this article to know about  RFT and its procedure to its normal range and result interpretation.  

An RFT is a medical test that measures how well the kidneys are working. It does this by checking the levels of waste products and other substances in the blood. 

A Kidney Function Test includes many components. Every component in the renal function test varies as per laboratory.

The most common measurements include:

1. Blood Urea/Blood Urea Nitrogen (BUN): This test examines blood urea nitrogen, a protein metabolism byproduct. It may also be referred to simply as urea. The kidneys eliminate blood urea, excreting it as urine.

2. Creatinine: It is a byproduct consistently produced during normal muscle activity. The kidneys remove creatinine from the blood, excreting it as urine.

3. Calcium: This is a vital mineral crucial for bone health, muscle function, the cardiovascular system, and the nervous system. An excess of calcium can increase the workload on the kidneys as they work to filter it.

4. Phosphorus: It is an essential mineral for teeth, bones, the nervous system, and muscles. This plays a role in maintaining the balance and utilization of other vitamins and minerals like vitamin D, iodine, magnesium, and zinc.

5. Uric Acid: This test evaluates a nitrogenous compound formed during the breakdown of purines. Uric acid is also produced from the metabolic breakdown of certain foods, such as red meat, seafood, and beans.

6. Sodium: It is an electrolyte acquired from our diet and is primarily regulated by the kidneys in the body.

7. Potassium: It falls into the category of electrolytes, which are minerals essential for maintaining acid-base balance, adequate fluid levels, and proper muscle and nerve function.

8. Chloride: This combines with other electrolytes to carry out multiple functions, including maintaining a healthy fluid balance in the body.

Early kidney disease has no noticeable symptoms. To ascertain the health of the kidneys, undergoing an RFT is a must.

Consider undergoing kidney function tests if the individual has the following:

1. Diabetes: If you're living with diabetes, it's recommended to have these tests annually.

2. Suffer from High Blood Pressure: High blood pressure is a known precursor to kidney issues. If an individual has this condition, regular testing is advisable.

3. Heart Disease: Individuals with a history of heart disease should also prioritize kidney function assessments. Heart problems and kidney health are closely linked.

4. Possess a Family History of Kidney Failure: If anyone in the family has a history of kidney failure, this increases the vulnerability of the condition.

RFT tests may be done if the following symptoms are observed:

1. Painful urination (Dysuria)

2. Blood in the urine (Haematuria)

3. Frequent urge to urinate

Individuals experiencing symptoms or having risk factors for kidney issues should undergo testing for early detection. This helps in initiating timely treatment to avert severe complications. The advantages of a Kidney Function Test include:

1. No fasting

2. No need for any additional special preparations

3. Minimal to no aftercare necessary

4. A swift and easy procedure.

5. Involves minimal risks

The doctor may request renal function test to assess the kidney health. There are 3 types of KFT, which are:

1. Blood Urea Nitrogen (BUN) Test: This test measures the nitrogen level derived from the breakdown of proteins in the blood.

2. Estimated Glomerular Filtration Rate (eGFR): It calculates the filtration rate of the kidney based on protein levels, age, gender, size, and race. It provides an estimate of how well the kidneys are functioning.

3. Serum Creatinine Test: This test detects the accumulation of creatinine, a waste product resulting from the breakdown of muscle tissue, in the blood. Elevated levels may indicate kidney dysfunction.

Additionally, the doctor may recommend 24-hour urine tests, which include:

1. Microalbuminuria Test: This test examines the presence of a specific protein called albumin in the urine. Elevated levels can be an early sign of kidney damage.

2. Urinalysis: It assesses the urine for the presence of blood, proteins, and overall kidney function. It provides valuable insights into kidney health.

Specific preparations are often required before the KFT to ensure accurate results. These include:

1. Fasting: Typically, no fasting is necessary before KFT. Individuals can eat and drink as usual before the test.

2. Medications: Inform the doctor about any medications or supplements, as some drugs can affect RFT results. They may advise to discontinue certain medicines before the test temporarily.

3. Avoiding Physical Activity: Avoid vigorous physical activity before the test, as it can affect RFT levels. Resting before the test can help obtain more accurate results.

A KFT takes less than 10 minutes. It is easy and causes minimal discomfort, ensuring an accurate kidney function test result. The procedure includes:

1. The person undergoing the test will be asked to sit in a comfortable chair.

2. A phlebotomist will examine the individual's arms, focusing on the inner part of the arm, typically on the side opposite to the elbow, in search of an easily accessible vein.

3. After locating the suitable vein, he will use an alcohol swab to thoroughly clean and sterilize the area.

4. Next, a small needle will be gently inserted into the identified vein. While this process may cause a minor pinch sensation, it is generally not very painful.

5. He will collect the necessary amount of blood into a test tube. This step is relatively quick and painless.

6. Once an adequate blood sample has been obtained, he will carefully remove the needle from the vein.

7. To prevent bleeding, a cotton ball or gauze will be applied briefly to the puncture site, facilitating clot formation.

8. Finally, a band-aid will be placed over the puncture site to cover and protect it. This marks the completion of the blood collection process.

There is no immediate after-care required after a KFT. A few aftercare measures can help ensure a smooth recovery. These include:

1. Rest and Recovery: After the test, take a moment to rest and recover to prevent lightheadedness during the procedure.

2. Stay Hydrated: Drink plenty of water to help the body recover and replenish fluids lost during the test.

3. Observe for Complications: Pay attention to the puncture site for any signs of infection, such as redness, swelling, or unusual pain.

4. Avoid Heavy Lifting: Refrain from heavy lifting or strenuous activities for a few hours after the test to prevent bleeding or bruising at the puncture site.

RFT reports are usually available to the patient on the same day. The reference range for the RFT may vary depending on the specific laboratory conducting the test. 

Interpretation of Renal Function Test

To diagnose kidney conditions, the RFT normal range is interpreted as follows:

1. Blood Urea Nitrogen - 7 - 20 mg/dL

2. Blood Urea - 10 - 50 mg/dL

3. Creatinine - Male: 0.6-1.2 mg/dL, Female: 0.5-1.1 mg/dL

4. Calcium - 8.5-10.5 mg/dL

5. Phosphorus - 2.40–4.40 mg/dL

6. Uric Acid - 3.4-7.0 mg/dL

7. Sodium - 135-148 mmol/L

8. Potassium - 3.5-5.0 mmol/L

9. Chloride - 98-106 mmol/L

Interpretation of High Renal Function Test

High kidney function test levels can indicate potential kidney issues or other health conditions. Understanding the common causes of elevated kidney function test results is crucial for maintaining overall health.

Interpretation of high levels in Kidney Function Test:

1. Dehydration: Insufficient fluid intake can lead to concentrated urine, causing temporary spikes in kidney function test results. Inadequate fluid intake can lead to concentrated blood and higher creatinine levels.  It can cause potassium to become concentrated in the blood. Excessive loss of fluids, through sweating or not drinking enough water, can raise sodium levels.

2. Infections: Kidney or urinary tract infections may result in elevated levels due to increased kidney stress.

3. Medications: Certain drugs, like nonsteroidal anti-inflammatory drugs (NSAIDs) and antibiotics, can affect kidney function test results.

4. Chronic Kidney Disease (CKD): Long-term kidney damage from diabetes or hypertension can lead to persistently high levels of KFT.

5. Kidney Stones: The presence of kidney stones may cause temporary spikes in kidney function markers.

6. Muscle Breakdown: Intense exercise or muscle injury can release substances that affect kidney function tests.

7. High Blood Pressure: Hypertension can harm the kidneys over time, leading to elevated kidney function levels.

8. Autoimmune Disorders: Conditions like lupus or vasculitis can cause kidney inflammation and affect test results.

Treatment after a kidney function test can vary depending on the results. No specific treatment may be necessary in case the results are normal. Regular checkups might be advised to monitor any conditions. 

The doctor will include the following in the treatment in case the results are not normal:

1. Lifestyle Changes: The doctor recommends lifestyle changes if early kidney problems are detected. It could be eating a healthier diet, drinking more water, and managing diabetes or high blood pressure.

2. Medications: If kidney disease is present, medications may be prescribed to control blood pressure, reduce protein in the urine, or manage underlying causes.

3. Dialysis: In severe cases of kidney disease or failure, dialysis may be required. Dialysis is a medical procedure that helps remove waste and excess fluids from your blood when your kidneys can't do it alone.

4. Kidney Transplant: For end-stage kidney disease, a kidney transplant may be an option. This involves receiving a healthy kidney from a donor.

Kidney function tests are safe. But minor risks can be involved, which can be resolved on its own. It includes:

1. Bruising: Occasionally, after blood tests, you may notice some bruising at the site where the blood was drawn. This is usually temporary.

2. Dizziness: Some individuals might experience temporary dizziness following the blood tests. It's usually short-lived and should subside quickly.

3. Fatigue: After undergoing kidney function tests, you may feel slightly more tired than usual. This fatigue is typically transient and should improve with rest.

Cost of RFT Test

It differs based on the city where the test is performed. The factors that affect the test cost include: 

1. Testing Location: The cost of a kidney function test can vary depending on where it is conducted. Hospitals, clinics, and diagnostic laboratories may have different pricing structures. Additionally, the specific diagnostic laboratory chosen can impact the cost, with variations in pricing between facilities.

2. Insurance Coverage: Individuals with health insurance may have some or all of the kidney function test cost covered by their insurance plan. However, the extent of coverage and the out-of-pocket expenses can vary significantly depending on the individual's insurance plan and policy terms.

3. Additional Testing: Sometimes, additional tests, such as blood glucose or other blood tests, may be required alongside the kidney function test. These additional tests can contribute to the overall cost of the testing process.

RFT tests are easy, safe, affordable, and accurate tests for detecting and managing kidney diseases. Book an appointment for home collection or visit a centre to get your samples collected. 

The healthcare team at HexaHealth is here to help. Our experts will assess your situation and provide you with personalised treatment options suitable for your condition.

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