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Kidney Function

eGFR Test (Estimated Glomerular Filtration Rate)

eGFR estimates how well your kidneys filter waste from your blood. It is calculated from your creatinine level, age and sex, and it is the single most important number for detecting chronic kidney disease early.

Written by Suman Konda, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last reviewed and updated: · How we check our content

Quick answer

eGFR estimates how well the kidneys filter blood, in mL/min/1.73m2; 90 or above is normal. Readings of 60-89 show mild decline, and below 60 persisting three months defines chronic kidney disease. eGFR falls naturally with age, so trends matter more than one result. A single low reading should be repeated, as dehydration or illness can depress it temporarily.

The short answer

eGFR estimates how well your kidneys filter blood, calculated from creatinine, age and sex. A normal eGFR is 90 or above. Readings of 60–89 suggest mild decline, and below 60 persisting for three months indicates chronic kidney disease. eGFR naturally falls with age, so trends matter more than one result.

What is an eGFR test?

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Your kidneys filter about 180 litres of blood every day through tiny units called glomeruli. The estimated glomerular filtration rate (eGFR) tells you, in millilitres per minute, how much blood your kidneys can filter, expressed per standard body surface area (mL/min/1.73m²).

You never have eGFR measured directly. Your lab calculates it from your blood creatinine using a standard formula (most labs now use the 2021 CKD-EPI equation), plugging in your age and sex. That is why eGFR always appears alongside creatinine on your report, it translates the raw creatinine number into an actual kidney-function estimate.

eGFR Normal Range

eGFR (mL/min/1.73m²)Kidney FunctionStage
90 or aboveNormalStage 1 (if kidney damage present)
60 – 89Mild declineStage 2
45 – 59Mild-to-moderate declineStage 3a
30 – 44Moderate-to-severe declineStage 3b
15 – 29Severe declineStage 4
Below 15Kidney failureStage 5

eGFR naturally falls with age, roughly 0.5 to 1 point per year after age 40, so the same number means different things at different ages. An eGFR of 70 in a healthy 75-year-old is often just normal ageing, while 70 in a 30-year-old deserves investigation. This is why doctors look at the trend over time, urine protein results and blood pressure alongside the number, not the number alone.

What does LOW eGFR mean?

LOW eGFR below 60

An eGFR below 60 that persists for three months or more meets the definition of chronic kidney disease (CKD), even if you feel perfectly well, early CKD usually has no symptoms. The most common causes are diabetes and high blood pressure, which together account for the majority of cases worldwide. Other causes include glomerulonephritis, polycystic kidney disease, long-term use of NSAID painkillers, and repeated urinary infections or obstructions. A single low reading should always be repeated: dehydration, a recent illness, or certain medicines can temporarily depress eGFR without any lasting kidney damage.

When eGFR is low, doctors check urine for protein (albumin), because protein in the urine plus a low eGFR paints a fuller picture of kidney damage than either test alone. Blood pressure control becomes the top priority.

eGFR vs creatinine: why both matter

eGFR vs creatinine

Creatinine is the raw waste product your muscles produce; eGFR is the interpreted result. The trap is that creatinine alone can look reassuring while kidney function is actually falling, an older adult with little muscle mass can have a “normal” creatinine of 1.0 mg/dL yet an eGFR of only 55. eGFR corrects for age and sex, so it catches decline that creatinine alone would hide. Read them as a pair: creatinine is the measurement, eGFR is the meaning.

Can eGFR improve?

Often, yes, especially in the early stages. Kidney damage from diabetes and hypertension progresses slowly, and the steps that slow it are well proven: keeping blood sugar and blood pressure in target range, cutting back on salt, staying well hydrated, avoiding NSAIDs and other nephrotoxic drugs unless necessary, and treating urinary infections promptly. If a low eGFR was caused by something reversible, dehydration, an acute illness, a new medicine, it frequently rebounds once the trigger is removed.

What eGFR cannot do is regenerate scarred kidney tissue. The goal of treatment is to protect the filtering units you still have and slow further loss, which is why catching a falling eGFR early matters so much.

Questions to ask your doctor

  • Is my eGFR low for my age, or could this be normal ageing?
  • Should we recheck it, and was there anything (dehydration, medicines) that could have lowered it temporarily?
  • Do I need a urine protein (ACR) test alongside?
  • Which of my medicines need dose changes at this level of kidney function?

eGFR myths vs facts

eGFR looks like a lab measurement but behaves like a calculation — which breeds specific misunderstandings. Here is what the evidence actually says:

MYTH eGFR is measured directly from my blood.

Fact: It is calculated — from your creatinine, age and sex — using an estimating equation. That is why the same creatinine gives different eGFRs at different ages, and why the result shifts if any input is off.

MYTH One low eGFR means chronic kidney disease.

Fact: CKD needs persistence: reduced eGFR or kidney damage markers lasting over 3 months. A single low value during dehydration, illness or after heavy exercise is rechecked, not labelled.

MYTH Drinking more water raises your eGFR.

Fact: Hydration corrects the dehydration-driven dip, but water doesn't improve kidney function. A persistently low eGFR when well hydrated needs evaluation, not more water.

MYTH Muscle mass doesn't affect eGFR.

Fact: It does, through creatinine: very muscular people read lower eGFRs and slightly built or older people read higher ones than their true filtration. Cystatin C — an alternative marker — is sometimes used when muscle mass distorts the picture.

MYTH A normal creatinine guarantees a normal eGFR.

Fact: The equation can flag a reduced eGFR while creatinine still sits inside its range — that is rather the point of calculating it. Read the eGFR line, not just the creatinine.

Your eGFR result: what to do next

Got your report and wondering what the number means for you? Find the branch that matches your situation — every path ends with your doctor, because eGFR is never interpreted alone:

If your result is…Sensible next stepTalk to your doctor when…
Mildly reduced (60–90), first timeOften rechecked in a few months with urine albumin; review blood pressure, diabetes control and medicines.it stays reduced on repeat, or urine shows protein.
Below 60 on repeatThis range defines kidney concern — cause-finding (diabetes, blood pressure, medicines) usually follows.promptly; persistent values here deserve proper evaluation.
Falling trend across reportsBring old reports — the slope matters most. Check for new medicines, dehydration or recent illness.the decline is steady, or swelling, fatigue or appetite loss appear.
Low during acute illnessUsually rechecked after recovery — acute illness and dehydration temporarily depress eGFR.it doesn't recover with the illness, or urine output drops markedly.

eGFR test price in India

In India, there is no separate charge for eGFR — it is calculated from your creatinine value, which arrives inside a kidney function test (KFT). A basic KFT typically costs &rupee;500–&rupee;1,000, varying by city and lab. NABL-accredited labs usually publish their rates online, so comparing a couple near you is worthwhile. For trend monitoring, use the same lab each time so the estimating equation stays constant.

Frequently Asked Questions

What is a normal eGFR by age?
A normal eGFR is 90 or above in young adults. It naturally declines by roughly 1 point per year after age 40, so a value in the 60s or 70s can be age-appropriate in an older adult with no other kidney problems.
At what eGFR should I worry?
An eGFR below 60 that persists for three months or more meets the definition of chronic kidney disease and needs medical follow-up. A single low reading should always be rechecked, as dehydration or illness can temporarily lower it.
Can eGFR improve?
Yes, often. Controlling blood pressure and blood sugar, staying hydrated, avoiding nephrotoxic medicines like NSAIDs, and treating the underlying cause can stabilise or improve eGFR, especially in early stages.
Why is my creatinine normal but my eGFR low?
Creatinine alone can look normal while eGFR is low because eGFR adjusts for age and sex. An older adult with less muscle can have a “normal” creatinine yet meaningfully reduced kidney function, which is exactly what eGFR reveals.
How often should eGFR be rechecked?
If your eGFR is normal and you have no risk factors, it is usually checked as part of routine annual blood work. With diabetes, hypertension or a low result, doctors typically recheck every 3 to 12 months.
My eGFR is 58 but I feel fine. Should I worry?
A single eGFR below 60 is a reason to repeat the test, not to panic — early kidney disease usually has no symptoms, which is exactly why the test exists. Chronic kidney disease is only diagnosed when a low eGFR persists for three months or more, so your doctor will likely recheck it, review your medicines and hydration, and add a urine albumin test before drawing conclusions. Discuss the plan with your doctor rather than interpreting one number alone.
Can dehydration lower my eGFR?
Yes, temporarily. When you are dehydrated, less blood reaches the kidneys and creatinine rises, which makes the calculated eGFR fall — without any lasting kidney damage. This is why doctors repeat a low eGFR when you are well-hydrated and not acutely ill before acting on it.
Why did my eGFR drop after starting blood pressure tablets?
Some blood pressure medicines, particularly ACE inhibitors and ARBs, can nudge creatinine up and eGFR down when started — this is usually expected and monitored, not a reason to stop the tablet on your own. Your doctor will weigh the small dip against the kidney protection these medicines provide. Never stop a prescribed medicine without medical advice.
Is an eGFR of 70 normal at 75?
Often, yes. eGFR falls naturally with age — roughly half to one point per year after 40 — so 70 in a healthy 75-year-old with no proteinuria is frequently just normal ageing. The same number in a 30-year-old deserves investigation. Age, trend, urine protein and blood pressure are read together.
How much does the eGFR test cost in India?
There is no single fixed price — it varies by city, lab, and whether the test is ordered alone or as part of a panel. NABL-accredited labs usually publish their rates online, so it is worth comparing a couple near you. Whatever you pay, the reference range printed on your own report is what counts — discuss the result with your doctor.

Pharmacist's practical notes

Because eGFR is calculated from creatinine, everything that moves creatinine moves eGFR: dehydration, muscle mass, creatine supplements, cooked-meat meals and several common medicines. A surprising eGFR deserves a recheck under calm conditions — well hydrated, rested, usual medicines disclosed — before any conclusion.

The medicine review is the highest-value step: NSAID painkillers, certain blood pressure drugs and some antibiotics all dent kidney function, sometimes reversibly. If eGFR fell after a new prescription, raise it with your doctor or pharmacist promptly — and never stop a prescribed medicine over a lab number without medical advice.

In India

Indian labs report eGFR in mL/min/1.73m², calculated from creatinine at no separate charge. A basic KFT typically costs &rupee;500–&rupee;1,000, varying by city and lab.

Choose a NABL-accredited lab and, for trend monitoring, use the same lab each time so the estimating equation stays constant.

Medical Disclaimer: This page is for general educational purposes only and does not constitute medical advice. Always consult a qualified doctor before making any health decisions.
Written and medically reviewed by Suman Konda, Clinical Pharmacist · Not medical advice, see our disclaimer