Your kidneys have a vital function of removing the waste, keeping fluids in balance, and overall health. Since your kidneys are not working, the waste will accumulate in your blood and cause fatal complications. A Renal Function Test (RFT), or kidney function test, will reveal how efficiently your kidneys are working. These tests are a key component to diagnose and treat diseases like chronic kidney disease (CKD) and acute kidney injury.

By monitoring such vital parameters as glomerular filtration rate (GFR), serum creatinine, electrolytes, and blood urea nitrogen (BUN), RFTs help to be helpful for an early diagnosis of regulation, Kidney health monitoring and renal function.

What is a Renal Function Test (RFT)?

A Renal Function Test (RFT) or renal profile test or kidney panel test is a battery of tests that assist to measure the function of kidneys in order for them to carry out their life-sustaining functions.
Tests are performed to examine urine and blood markers that show the renal function in an attempt to:

  • Exclude waste products
  • Control electrolyte balance
  • Control fluid balance
  • Control blood pressure

Major test items of RFT are:

  • Serum Creatinine Test
  • Blood Urea Nitrogen (BUN) Test
  • Glomerular Filtration Rate (GFR)
  • Chronic kidney disease test
  • Uric Acid Test
  • Electrolyte Levels (Sodium, Potassium, Chloride, Bicarbonate)
  • Creatinine Clearance Test
All the tests inform us regarding various functions and diagnoses of kidneys from mild dehydration to renal failure that is life-threatening.

Why Is the Renal Function Test Done?

Renal Function Test is a valuable test in diagnosis and management of the most prevalent kidney disorders. It is always advised in the form of signs and symptoms of deterioration of functioning of kidneys or risk factors which can impact functioning of kidneys. Regular follow-up also is made, predominantly in the form of patients being chronic in nature or on long-term therapy.

RFTs also identify acute kidney injury and chronic Kidney disease diagnosis (CKD) so that the latter two get treated within time. RFTs are prescribed in a majority of diabetic and hypertensive patients as such diseases deteriorate kidneys after some time. Nephritis, kidney stones, and UTI ruin kidneys and therefore get diagnosed on a regular basis as well.

Medication patients who are under medications that interfere with renal functions, i.e., painkillers or antibiotics, will need RFTs to check for adverse side effects. Surgical and kidney transplant recipients will find the test useful in enabling the healthcare personnel to keep an eye on healing and functioning of the organ.
Early detection of kidney damage using RFT results in successful management of diseases, life-style alteration, and prevention.

Preparation for Renal Function Test

Preparation for a kidney function test is easy and usually takes little effort. But good results are guaranteed by following simple rules.
Preparation rules:

  • Do not fast unless told to do so by your doctor.
  • Drink plenty of water, kidney function tests are dehydration-sensitive.
  • Tell your doctor about all your medicines and supplements because some of them influence the test results.
  • Avoid strenuous exercise before the test, which temporarily increases creatinine concentration.
  • Loose clothes if urine sample has to be taken.
  • Nothing at all for food or fluids, except as advised by your physician.

Read More: Urine C/E (Complete Examination) Test – Purpose, Procedure & Results


Procedure for RFT: What Is Done During the Test?

Procedure for renal function test is rapid, painless, and simple. Either it is a blood test or in certain situations a urine sample.
Steps Involved:

  • Blood Test: A blood sample will be drawn from a vein in your arm. It will be tested for serum creatinine, BUN, GFR, and electrolytes.
  • Drawing Urine Sample: Sometimes a 24-hour urine sample will need to be drawn to be tested for creatinine clearance or protein content.
  • Blood or Urine Tests: The lab performs tests on the blood or urine that is drawn. Test results take hours or days.
Only a few minutes, painlessly.

What Happens After the RFT?

You may resume your usual activity immediately after the test. No residual side effects.
Post-Test Considerations:

  • Bruising and soreness at blood draw site anticipated.
  • Give fluids to reverse transient rise in creatinine as stress reaction.
  • Inform your physician if you experience abnormal test results, particularly if you are taking medication that affects kidney function.
  • Early treatment upon verification of your RFT results provides early treatment in the event of abnormal outcomes.

RFT Result Interpretation

Kidney Function Test (RFT) reports provide valuable feedback about the efficiency with which your kidneys remove the waste products and help to preserve the inner equilibrium of the body. Each of the tests to be performed is another function of the kidneys, and their proper interpretation by physicians is helpful in early diagnosis of any upcoming problem.

Normal and Abnormal Values

  • Creatinine: Elevated creatinine is a sign of poor filtering by the kidneys, usually before kidney disease.
  • Blood Urea Nitrogen (BUN): Elevated BUN is evidence of renal injury, dehydration, or overconsumption of protein.
  • Glomerular Filtration Rate (GFR): GFR less than 60 for over three months and 60 or more than or equal to a CKD marker.
  • Uric Acid: High uric acid is a sign of gout or formation of kidney stones.
  • Electrolytes: Abnormal sodium, potassium, or bicarbonate level suggests acid-base derangement or fluid overload.
Unless abnormal result is not within the Normal kidney function levels, ultrasound, CT scan, or kidney biopsy will be ordered by physicians as tests.

Conditions Diagnosed by RFT

Renal and systemic disease is diagnosed through the assistance of renal function test, particularly with nonspecific and indefinite presentation.
Conditions Diagnosed Include:

  • Chronic Kidney Disease (CKD)
  • Acute Kidney Injury (AKI)
  • Glomerulonephritis
  • Kidney stone and infection
  • Hypertensive nephropathy
  • Diabetic nephropathy
  • Nephrotic syndrome
  • Polycystic kidney disease (PKD)
Drug-dependent patients, i.e., NSAIDs, antibiotics, or chemotherapy, RFTs are equally relevant.

Renal Function Test vs Kidney Function Test

RFT and KFT are identical. Both imply the same tests that are a test of kidney function.
Key Points:

  • RFT and KFT are a bit different
  • Both make use of markers such as creatinine, BUN, GFR, and electrolytes in reports
  • May differ slightly geographically or laboratory nomenclature
  • Other tests are added to kidney panel test in certain instances based on what medical condition has to be tested.

Cost of RFT in Pakistan

Price of Renal Function Test varies based on city, lab, and quantity of markers would be included in the test.
Estimated Price Range:

  • PKR 1,000 - PKR 3,500
  • Thin profiles are cheap, complete renal panels are costly
  • Payment for this test is covered by some medical insurance policies
  • Always bargain from the diagnostic centers or hospitals of a region.

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