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Draft: not yet reviewed by a clinician

Use this page to prepare questions for your care team. It does not replace their advice. Your own targets and doses come from your nephrologist, diabetes team and renal dietitian.

eGFR and creatinine

In short

Creatinine is a waste product your muscles make every day. Healthy kidneys filter it out, so when kidney function falls, creatinine in the blood rises. eGFR (estimated glomerular filtration rate) turns your creatinine, age and sex into an estimate of how much fluid your kidneys filter out of the blood each minute (NKF). NIDDK calls an eGFR of 60 or more the normal range and 15 or less kidney failure (NIDDK). Under 60 for 3 months or more means chronic kidney disease, and under 15 is stage G5 (KDIGO 2024). It is an estimate, so look at the trend over several tests, and know what can fool it.

Your numbers

Typical (your lab's range wins)
Creatinine, men 0.7–1.3 mg/dL
Creatinine, women 0.5–0.95 mg/dL
eGFR 60 or more mL/min/1.73 m² is in the normal range
Typical (your lab's range wins)
Creatinine, men 62–115 µmol/L
Creatinine, women 44–84 µmol/L
eGFR 60 or more mL/min/1.73 m² is in the normal range

Creatinine ranges from MedlinePlus. To convert creatinine, multiply mg/dL by 88.4 to get µmol/L (KDIGO 2024). eGFR uses the same unit everywhere.

eGFR (mL/min/1.73 m²) Stage In plain words
90 or more G1 normal filtering; CKD only if there is other damage, such as albumin in the urine
60–89 G2 mildly lower
45–59 G3a mildly to moderately lower
30–44 G3b moderately to severely lower
15–29 G4 severely lower
under 15 G5 kidney failure

One result does not set your stage: the low value has to last 3 months or more (KDIGO 2024). More on stages: CKD stages.

How often: at least once a year with CKD, and 1–4 times a year depending on your stage (ADA 2026 §11, recommendation 11.1b).

How eGFR is worked out

US labs use the CKD-EPI 2021 equation. It uses creatinine, age and sex, and it no longer uses race (NKF; KDIGO 2024, practice point 1.2.4.2). Labs report it rounded and per 1.73 m² of body surface, and flag results under 60 as low (KDIGO 2024, Table 11).

Why age and sex matter. Creatinine comes from muscle, and muscle mass differs on average by age and sex. The equation adjusts for that. Examples, worked with the CKD-EPI 2021 equation:

Person Creatinine eGFR
Woman, 60 1.4 mg/dL (124 µmol/L) about 43 (G3b)
Man, 60 1.4 mg/dL (124 µmol/L) about 58 (G3a)
Woman, 30 1.0 mg/dL (88 µmol/L) about 78 (G2)
Woman, 75 1.0 mg/dL (88 µmol/L) about 59 (G3a)

The same creatinine can mean different kidney function. That is why you should look at your eGFR, not only your creatinine.

When cystatin C is better

Cystatin C is another blood marker of filtering. It depends much less on muscle. KDIGO recommends adding it (an "eGFRcr-cys") when the creatinine estimate is likely to be wrong and the answer matters for treatment (KDIGO 2024, recommendation 1.2.2.1). Examples from KDIGO's list (Table 8):

  • very muscular people, bodybuilders, or extreme exercise;
  • an above-knee amputation, spinal cord injury, or muscle-wasting disease;
  • eating disorders, malnutrition, or severe obesity (a BMI over about 35–40);
  • unusual diets: very low or very high protein, vegetarian, keto, or creatine supplements;
  • serious illness: cancer, heart failure, cirrhosis;
  • some medicines, such as steroids, drugs that block how the kidney removes creatinine, or some broad-spectrum antibiotics.

Using creatinine and cystatin C together is more accurate than either one alone (KDIGO 2024, practice point 1.2.2.6).

What can fool creatinine

What happens Effect What to do
A cooked meat or fish meal In one study creatinine rose by about 0.23 mg/dL (20 µmol/L), peaking 2–4 hours later; in that group eGFR looked about 20 points lower Skip a big meat or fish meal for about 12 hours before the test if you can (KDIGO 2024, practice point 1.2.2.4)
Creatine supplements or a very high-protein diet creatinine reads higher, eGFR lower Tell your team; ask about cystatin C (KDIGO 2024, Table 8)
A lot of muscle, or very little high muscle: eGFR looks too low; low muscle or amputation: eGFR looks too high Ask about cystatin C (KDIGO 2024, Table 8)
Some medicines, such as trimethoprim or cimetidine can change creatinine without changing filtering Tell the team every medicine you take (MedlinePlus)
A sudden illness (vomiting, dehydration) eGFR lags behind real changes in kidney function Tell your team; the test is often repeated when you are well (KDIGO 2024, Table 9)
Starting an ACE inhibitor, ARB, finerenone or SGLT2 inhibitor an expected small dip, because these medicines lower the pressure inside the filters to protect them See the next section

The expected dip with kidney-protecting medicines

ACE inhibitors, ARBs, finerenone and SGLT2 inhibitors often lower eGFR a little in the first weeks. This is expected and is part of how they protect the kidneys. (With type 1 diabetes, SGLT2 inhibitors are not approved for glucose control and markedly raise the risk of DKA (Farxiga label); see Kidney-protecting medicines.)

  • KDIGO: keep taking an ACE inhibitor or ARB unless creatinine rises by more than 30 % within 4 weeks of starting or a dose increase. After starting any of these medicines, an eGFR fall of more than 30 % is more than expected and is looked into. Blood pressure, creatinine and potassium are checked 2–4 weeks after a start or a dose change (KDIGO 2024, practice points 2.1.4, 3.6.2, 3.6.4).
  • ADA: a creatinine rise of up to 30 % on these medicines "must not be confused with" acute kidney injury (ADA 2026 §11).
  • Finerenone: the label describes a small eGFR drop (on average 2–3 mL/min) in the first 4 weeks that then levels off (Kerendia label).

Never stop one of these medicines on your own because of a dip. Ask your team whether the change is in the expected range.

What to do

  • Learn your latest eGFR and the one before it, and the change in per cent.
  • Before the test, skip a big meat or fish meal for about 12 hours if you can, and do not take creatine supplements.
  • Tell your team about big changes in exercise, weight, diet or muscle mass. Ask whether cystatin C would help.
  • Tell every doctor, dentist and pharmacist your eGFR: many medicines are dosed by kidney function (KDIGO 2024, practice point 4.2.1).
  • After starting or increasing a kidney-protecting medicine, go for the blood test 2–4 weeks later.
  • Track the trend on the lab tracker.

In the app

Enter a creatinine (mg/dL or µmol/L), a cystatin C, or the eGFR printed on your report under Labs. The app works out CKD-EPI 2021 and suggests a G stage, but never changes the stage saved in your profile: one result is not enough (design note 05). It needs your age (18 or over). If your sex is not set, it shows both the female and the male result. It does not calculate eGFR in pregnancy, because the equations were not built for it.

Examples

  • Same number, different meaning. Maria and her brother are both 60 and both have a creatinine of 1.4 mg/dL. Her eGFR is about 43 (G3b); his is about 58 (G3a).
  • Starting an ACE inhibitor. Sam's eGFR was 50. Three weeks after starting an ACE inhibitor it is 44, a 12 % dip: expected, and the medicine continues. If it had fallen to 33 (a 34 % drop), his team would review it (KDIGO 2024, practice points 2.1.4 and 3.6.4).
  • The steak dinner. Lee had a large steak the night before an early blood test, and his eGFR came back lower than usual. His team repeated it after a light evening meal, and it was back to his normal level.
  • On dialysis. eGFR is not used to judge dialysis. Your unit checks how well dialysis works with other tests (KDOQI 2015; Dialysis adequacy).

Ask your care team

  1. What is my eGFR trend over the last year, in per cent?
  2. Is creatinine a good guide for me, or should we add cystatin C?
  3. When should my next blood test be after this medicine change?
  4. Are any of my medicines dosed by my eGFR?
  5. Is my eGFR low enough that we should talk about kidney failure treatment options?

Get help now if…

eGFR on its own is rarely urgent, but a fast fall can come with warning signs.

Call 911 (or your local emergency number)

Severe breathlessness, being unable to lie flat, chest pain, new confusion, or a lab potassium of 6.5 mmol/L or more (KDIGO 2024, Table 28). See Get help now.

Call your care team today

Much less urine than usual, new swelling, or vomiting or diarrhea so you cannot keep fluids down (start your sick-day plan). Also call if a result shows eGFR fell by more than 20 % with no clear reason (KDIGO 2024, practice point 2.1.3).

Sources

Not yet reviewed by a clinician. Facts and sources last checked 2026-10-06.