What does an eGFR of 30 mean?
An eGFR of 30 mL/min/1.73m² sits at the bottom edge of KDIGO band G3b, described as "moderately to severely decreased" filtering, right next to band G4. This is a result to take to a doctor soon — within days rather than at your next routine visit — but it is not what guidelines call kidney failure, which is band G5, under 15. It also does not stage chronic kidney disease by itself: that needs the level to stay there beyond three months, alongside a urine test for albumin.
30 mL/min/1.73m² is the conventional unit used by KDIGO and by labs in most countries. In SI units the same result is 0.50 mL/s/1.73m², since 1 mL/min/1.73m² is about 0.0167 mL/s/1.73m². A report showing 0.50 from another country is describing the identical result.
What this test measures
eGFR stands for estimated glomerular filtration rate — an estimate of how much blood the microscopic filters in your kidneys clean each minute. The "1.73m²" means the number has been adjusted to a standard adult body size so people of different builds can be compared. It is an estimate rather than a direct measurement: the lab measures creatinine, a waste product your muscles release into the blood, and an equation converts it using your age and sex. At this level the estimate is generally more reliable than it is at the top of the scale, but it can still be pulled off course by very high or very low muscle mass, a recent illness or infection, dehydration, pregnancy, and some medicines. Labs also use different versions of the equation, so a number from one place is not always exactly comparable with a number from another.
Where 30 mL/min/1.73m² sits
The KDIGO chronic kidney disease guideline sorts eGFR into "G stages", all in mL/min/1.73m²: G1 is 90 or above, G2 is 60–89, G3a is 45–59, G3b is 30–44 (moderately to severely decreased), G4 is 15–29, and G5 is under 15, which is the band KDIGO calls kidney failure. A result of 30 sits at the very bottom of G3b, one point above G4 — close enough to the line that ordinary variation between tests can move it either way, which is one more reason doctors watch trends rather than single figures. Even here, KDIGO does not stage chronic kidney disease from one blood test. Staging needs the result to persist beyond three months and needs the second axis of the chart: a urine test measuring albumin (albumin-to-creatinine ratio, or ACR). What this number means for you can only be worked out by a doctor who can see all of it together.
What to do next
- Contact the doctor or clinic that ordered the test within the next few days, and sooner if this is a large drop from your last result. Do not wait for a routine appointment or for a letter to arrive.
- Take every kidney result you can find with you. Whether 30 is new, or has been steady for years, changes the conversation more than the number itself does.
- Bring a complete list of everything you take — prescribed, bought without a prescription, herbal, traditional or supplement. Some things need reviewing when filtering is reduced, and that review is your doctor's job, not something to attempt yourself.
- Ask whether a urine albumin test (ACR) has been done and what it showed, and ask when the blood test will be repeated.
- Ask what would count as a reason to come back sooner, so you leave with a clear plan rather than a number.
Common questions
Is an eGFR of 30 kidney failure?
No. KDIGO reserves the term kidney failure for band G5, under 15. Thirty sits at the bottom of band G3b, described as moderately to severely decreased, just above G4. It is a result that needs a doctor's review soon, but that is not the same thing as failure.
How quickly should I see a doctor?
Contact the clinic that ordered the test within a few days rather than waiting for a routine appointment — and sooner if this is a big fall from your previous result. If you also have any of the warning signs listed above, treat it as an emergency instead and get help the same day.
Does an eGFR of 30 mean dialysis is coming?
Not necessarily, and certainly not on the basis of one reading. Many people live for years at this level without ever reaching that point, and decisions like that are never made from a single number. It is a fair question to put to your doctor, who can answer it with your whole record in front of them.
Can an eGFR of 30 go back up?
It can, particularly when something short-term — an illness, dehydration, or a recent change in what you take — pushed it down. It may also stay roughly where it is. A repeat test is how that difference is worked out, so make sure one is arranged rather than assuming either outcome.
What is the difference between stage G3b and stage G4?
They are neighbouring bands on the same scale: G3b is 30–44 and G4 is 15–29 mL/min/1.73m². A result of exactly 30 sits at the very bottom of G3b, so normal variation between tests can move it across the line in either direction. That is one reason doctors watch the trend rather than reacting to a single figure.
Why do I feel completely fine?
Feeling well at this level is common. Symptoms such as tiredness, poor appetite, itching, swelling or breathlessness tend to appear later, and some people never get strong symptoms at all. Feeling fine is genuinely good, but it is not a reason to delay the follow-up.
Should I stop taking something I am on?
Do not stop or change anything on your own — that can be more dangerous than the result. Bring a full list of everything you take, including anything bought without a prescription and any herbal or traditional products, and let your doctor decide what, if anything, needs adjusting.
Could the number be wrong?
Any single estimate can mislead, and labs differ in equipment and in which version of the equation they use. Your doctor may repeat the blood test, and may arrange a different type of blood test to cross-check the estimate. Getting it rechecked is normal practice, not a sign that anyone doubts you.