A Kidney Function Test report is full of numbers and abbreviations that most people have never seen before. This guide explains every value weather it is creatinine, urea, uric acid, eGFR, or electrolytes in plain, simple language. You will learn what each marker means, what high or low values typically indicate, and when a slightly abnormal result is a temporary blip versus something that needs attention. By the end, you will have a clear list of questions to take to your next doctor visit.
You got a kidney function test done. The lab sent you a report full of numbers, abbreviations, and reference ranges. You look at it and honestly, it means nothing to you.
Is creatinine supposed to be this high? What even is BUN? And why does eGFR have a number that looks worrying?
If you are sitting with that report right now, this guide is for you. We will walk through every value in plain simple language, no medical background needed.
What is a Kidney Function Test?
A Kidney Function Test, or KFT, is a group of blood tests that check how well your kidneys are working. You might also see it called a Renal Function Test (RFT) or Kidney Profile on your lab report. They are all the same thing.
Your kidneys filter your blood all day, remove waste and extra water, and send it out as urine. The KFT measures how well that filtering is happening by looking at the waste products left behind in your blood.
Think of it like the filter in a water purifier. If the filter is working well, waste gets cleared out. If it is clogged or damaged, waste starts building up. The KFT checks whether your kidney filter is doing its job.
Why Do Doctors Order a KFT?
It is one of the most commonly ordered blood tests in India, and most of the time it is completely routine. Some common reasons include:
- You went for a full body checkup or preventive health package
- You have diabetes or high blood pressure, both of which can affect kidneys over time
- You have been on certain medicines like painkillers or antibiotics for a long time
- You are having symptoms like swelling in the legs, reduced urine output, or unusual fatigue
- Follow-up after a kidney infection or urinary tract infection
The KFT Panel Explained
Creatinine
What it is: Creatinine is a waste product that your muscles naturally produce when they do their normal work. Your kidneys filter this out of your blood and remove it through urine.
What high creatinine means: When creatinine builds up in the blood, it usually means the kidneys are not filtering it out fast enough. But it can also go up for much simpler reasons that have nothing to do with kidney disease.
Normal range: 0.7 to 1.3 mg/dL for men, 0.6 to 1.1 mg/dL for women. Always compare against the reference range printed on your own report, not a number you found online.
Source: Metropolis India and Medscape Lab Reference Ranges
What can temporarily raise creatinine:
- Dehydration that is not drinking enough water before the test is the most common reason
- Heavy exercise the day before
- Eating a lot of red meat or high-protein food before the test
- Certain medicines including some painkillers and antibiotics
A slightly elevated creatinine in a young person who was dehydrated is very different from a consistently high creatinine in someone with diabetes. One mildly elevated reading on its own does not confirm kidney disease.
Blood Urea Nitrogen (BUN) and Urea
What it is: When your body breaks down protein from food like dal, chicken, eggs, paneer. It produces a waste called urea. BUN stands for Blood Urea Nitrogen and measures the amount of urea in your blood. Some reports show BUN, others show Urea, some show both. They are measuring the same thing from slightly different angles.
What high values mean: High urea or BUN can mean the kidneys are not clearing this waste efficiently. But it is also very commonly elevated due to dehydration, eating more protein than usual, or even constipation.
Normal range: Urea approximately 15 to 40 mg/dL. BUN approximately 5 to 20 mg/dL.
Source: NIH/NCBI Clinical Methods, BUN and Creatinine chapter and Medanta Health Blog
Doctors sometimes look at the ratio of BUN to creatinine together. A very high ratio often points to dehydration rather than actual kidney damage. This is a useful clue your doctor uses to tell the difference between a temporary blip and something that needs further investigation.
Uric Acid
What it is: Uric acid is a waste product formed when your body breaks down substances called purines. Purines are found in red meat, certain fish, alcohol, and also naturally in your own cells. The kidneys filter uric acid and remove it through urine.
What high uric acid means: When uric acid builds up in the blood, it can form crystals. These crystals can settle in joints and cause gout, a condition that leads to sudden, severe joint pain, most commonly in the big toe. Over time, high uric acid can also contribute to kidney stones.
Normal range: 4.0 to 8.5 mg/dL for men, 2.7 to 7.3 mg/dL for women.
Source: Medscape Lab Reference Ranges
Many people have high uric acid with no symptoms at all. It becomes a concern mainly when it stays consistently high, especially if there is existing joint pain or a history of kidney stones.
eGFR — Estimated Glomerular Filtration Rate
This is probably the most important number in your kidney report and also the one that causes the most confusion.
What it is: eGFR stands for Estimated Glomerular Filtration Rate. The word glomerular refers to tiny filtering units inside your kidney called glomeruli. The eGFR is a calculated estimate of how many millilitres of blood your kidneys are filtering per minute.
Put simply, it tells you what percentage of kidney function is currently working.
A healthy person has an eGFR of 90 or above. An eGFR below 60, especially if it stays that way over 3 or more months, is when doctors start looking more carefully.
How it is calculated: The lab does not measure eGFR directly. It calculates it using your creatinine level, your age, and your sex. It is an estimate, not an exact measurement, but it is a very useful clinical guide.
The eGFR Stages Explained Simply
Stage 1 — eGFR 90 or above: Normal kidney function. If you are here with no other abnormalities, you are fine.
Stage 2 — eGFR 60 to 89: Mildly reduced. For many people, especially older adults, this is normal variation and not a cause for immediate concern on its own.
Stage 3 — eGFR 30 to 59: Moderately reduced. Your doctor will likely want to investigate further and may refer you to a kidney specialist called a nephrologist. This does not mean kidney failure. It means the kidneys need monitoring and care.
Stage 4 — eGFR 15 to 29: Severely reduced. You will be under the care of a nephrologist and conversations about future treatment options will begin.
Stage 5 — eGFR below 15: Kidney failure. At this stage the kidneys can no longer function adequately on their own and treatment such as dialysis or a kidney transplant becomes necessary.
One thing to keep in mind: a single eGFR reading that is slightly low does not confirm kidney disease. Dehydration or a recent illness can temporarily bring eGFR down. Kidney disease is only diagnosed based on two or more readings over at least 3 months, not a single test.
Electrolytes — Sodium, Potassium, Chloride, and Bicarbonate
Many KFT panels also include electrolytes. These are minerals in your blood that control fluid balance, nerve signals, muscle movement, and your heartbeat.
Sodium (Na): Controls fluid balance in the body. Low sodium can cause weakness and confusion. High sodium usually means dehydration. Normal range is around 136 to 145 mEq/L.
Potassium (K): Critical for heart and muscle function. High potassium, a condition called hyperkalemia, can affect heart rhythm and is one of the key reasons damaged kidneys need careful monitoring. Normal range is around 3.5 to 5.0 mEq/L.
Chloride (Cl): Works alongside sodium to maintain fluid balance. Rarely looked at in isolation. Normal range is around 98 to 107 mEq/L.
Bicarbonate (HCO3): Tells you about the acid-base balance in your blood. When kidneys are not working well, bicarbonate can drop, making your blood more acidic. This is called metabolic acidosis. Normal range is around 22 to 29 mEq/L.
Source for all electrolyte ranges: Medscape Lab Reference Ranges
What Does a Normal KFT Report Look Like?
The ranges below are based on standard adult reference values verified from Medscape Lab Reference Ranges, NIH/NCBI Clinical Methods, and Metropolis India
| TEST | Approximate Normal Range |
|---|---|
| Creatinine (Men) | 0.7 to 1.3 mg/dL |
| Creatinine (Women) | 0.6 to 1.1 mg/dL |
| Urea | 15 to 40 mg/dL |
| BUN (Blood Urea Nitrogen) | 5 to 20 mg/dL |
| Uric Acid (Men) | 4.0 to 8.5 mg/dL |
| Uric Acid (Women) | 2.7 to 7.3 mg/dL |
| eGFR | 90 or above |
| Sodium | 136 to 145 mEq/L |
| Potassium | 3.5 to 5.0 mEq/L |
| Chloride | 98 to 107 mEq/L |
| Bicarbonate | 22 to 29 mEq/L |
Always compare your result against the reference range your own lab has printed. Different machines can vary slightly.
High Creatinine or Urea — Does It Always Mean Kidney Damage?
No. And this is probably the most important thing to take from this guide.
The most common reason for a mildly elevated creatinine or urea in an otherwise healthy person in India is dehydration. If you did not drink much water before the test, spent time in the heat, had loose motions, or were running a fever, creatinine can come up higher than normal without any kidney disease involved.
Other temporary causes:
- High protein diet: Eating a lot of non-veg food, especially red meat, right before the test can raise both creatinine and urea.
- Heavy exercise: Intense gym workouts or physical labour break down more muscle and produce more creatinine.
- Medicines: Common painkillers like ibuprofen and diclofenac, as well as some antibiotics, can raise creatinine temporarily.
- Fever or infection: When the body is fighting an illness, kidneys work under more stress, and this can temporarily show up in the numbers.
If you have one mildly elevated reading with no symptoms and an otherwise normal report, the first step is usually just to drink more water and repeat the test.
When Should You See a Doctor?
In India, access to a doctor is rarely a week-long wait. If your report is worrying you, you can typically see your family doctor or a general physician at a nearby clinic the same day or the next day. You do not need to sit at home feeling anxious about a number on a report.
Go see your doctor soon if:
- Creatinine or urea is elevated and you also have swelling in the legs or face, reduced urine output, or unusual fatigue
- Your eGFR is below 60 on this reading
- You have diabetes or high blood pressure and your values are outside range
- Your potassium is elevated — do not wait on this one, high potassium can affect heart rhythm
Repeat the test first before worrying, if:
- You have a mild elevation with no symptoms at all
- You were dehydrated, had a fever, or ate heavy protein before the test
- The rest of your report is normal and this is your first KFT ever
See a kidney specialist (nephrologist) if:
- Your eGFR has been below 60 on two tests at least 3 months apart
- Your doctor has already advised a referral
- Creatinine or urea has been consistently high across multiple tests
Questions to Ask Your Doctor
Going prepared makes your consultation much more useful. Here are specific questions worth asking:
- Is this elevated creatinine something we act on now or watch and retest?
- Could dehydration or my diet have affected this result?
- Do I need to repeat this test, and how soon?
- Should I cut down on any of my current medicines, especially painkillers?
- Does my eGFR reflect a real concern or is it likely a temporary dip?
- Do I need to see a kidney specialist?
- Should I change anything in my diet or water intake for now?
FAQs
Q: My creatinine is 1.4 mg/dL. Is that dangerous?
Not necessarily. A mildly elevated creatinine is often caused by dehydration, heavy exercise, or a high-protein meal before the test. Drink more water and repeat the test before drawing any conclusions.
Q: My eGFR is 58. Does that mean I have chronic kidney disease?
A single reading of 58 is not a diagnosis. Chronic kidney disease is only confirmed when eGFR stays below 60 on two tests at least 3 months apart. Repeat the test first.
Q: Can drinking more water improve my kidney test results?
Yes, in many cases. Dehydration is one of the most common reasons for temporarily elevated creatinine and urea. Staying well hydrated before retesting often brings values back to normal.
Q: Is a high uric acid reading serious?
Not always. Many people have high uric acid with no symptoms. It becomes a concern when it stays consistently high alongside joint pain or a history of kidney stones.
Q: My potassium came back high. Should I be worried?
High potassium needs prompt attention because it can affect heart rhythm. Do not wait on this one. See your doctor the same day.
Q: What foods should I avoid if my KFT values are abnormal?
Reducing red meat, excess salt, alcohol, and high-purine foods like organ meats is a good starting point. Your doctor will give specific guidance based on which values are abnormal.
This guide is written to help you understand your report. It does not replace your doctor's advice. If your values are outside range or you have symptoms, see a doctor.
