eGFR 35: What It Means (CKD Stage G3b)
An eGFR of 35 mL/min/1.73m² is KDIGO category G3b (30 to 44). This page explains what it means, the creatinine behind it, and what to ask next.
Medically reviewed by Dr. Rishi Kumar Kafle, MBBS, MD, FASN. Last reviewed October 2026.
An eGFR of 35 mL/min/1.73m² falls in KDIGO category G3b (30 to 44), which means moderately to severely decreased filtration. At age 50 it matches a creatinine of about 2.23 mg/dL in a man and 1.75 mg/dL in a woman. Below 60 for more than three months meets the KDIGO definition of chronic kidney disease even without albuminuria, so a repeat test is needed to confirm it.
Where 35 Sits Within G3b
An eGFR of 35 is 5 points above the G3b floor of 30. It is 10 points below the G3a line at 45. The KDIGO categories run from G1 to G5; G3b is explained in more depth on the CKD stage 3 page.
G3b is moderately to severely decreased filtration. Many medicines that leave the body through the kidneys need a dose check at this level, and follow-up blood and urine tests are usually more frequent than in G3a.
What Creatinine Gives an eGFR of 35?
The creatinine behind an eGFR of 35 comes from solving the race-free CKD-EPI 2021 equation backwards, by age and sex:
| Age | Man | Woman |
|---|---|---|
| 30 | 2.47 mg/dL (219 µmol/L) | 1.94 mg/dL (172 µmol/L) |
| 40 | 2.35 mg/dL (208 µmol/L) | 1.85 mg/dL (163 µmol/L) |
| 50 | 2.23 mg/dL (197 µmol/L) | 1.75 mg/dL (155 µmol/L) |
| 60 | 2.12 mg/dL (187 µmol/L) | 1.66 mg/dL (147 µmol/L) |
| 70 | 2.01 mg/dL (178 µmol/L) | 1.58 mg/dL (140 µmol/L) |
| 85 | 1.86 mg/dL (165 µmol/L) | 1.46 mg/dL (129 µmol/L) |
A 30-year-old man reaches 35 at 2.47 mg/dL, while an 85-year-old woman reaches it at 1.46 mg/dL. The older the person, the lower the creatinine behind the same eGFR. Nearby creatinine guides: creatinine 1.6 mg/dL (141 µmol/L), creatinine 2.0 mg/dL (177 µmol/L), creatinine 2.5 mg/dL (221 µmol/L).
eGFR 35 in Absolute mL/min
eGFR is indexed to a body surface area (BSA) of 1.73m². To compare it with a creatinine clearance, or for a very small or large adult, it can be de-indexed with eGFR × BSA ÷ 1.73. For an eGFR of 35, the absolute values are:
| Example adult | BSA (m²) | Absolute GFR (mL/min) |
|---|---|---|
| Man, 40, 178 cm, 80 kg | 1.99 | 40 |
| Woman, 65, 163 cm, 62 kg | 1.67 | 34 |
| Woman, 82, 157 cm, 48 kg | 1.45 | 29 |
| Man, 55, 175 cm, 118 kg | 2.40 | 48 |
What Changes at an eGFR of 35
35 is 5 points above 30, and a fall of about 17% would cross that line. Below 30, KDIGO advises sharing care with a kidney specialist (nephrologist). It is already below 60.
5 of the 9 medicines in our registry whose labels use eGFR have a rule in force at 35. No eGFR-based rule in the registry starts between 40 and 35.
| Medicine | At eGFR 35 | Next change if eGFR falls |
|---|---|---|
| Metformin | not to be started; the registry advises halving an existing dose | at 29 or lower: contraindicated |
| Sitagliptin | dose lowered to 50 mg | at 29 or lower: dose lowered to 25 mg |
| Saxagliptin | dose lowered to 2.5 mg | none lower in the registry |
| Dapagliflozin | glucose-lowering effect limited | at 24 or lower: below the floor of 25 the registry gives for its kidney disease use |
| Empagliflozin | no eGFR rule in force | at 29 or lower: glucose-lowering effect limited; other uses follow the indication |
| Canagliflozin | no eGFR rule in force | at 29 or lower: use limited; depends on the indication |
| Spironolactone | no eGFR rule in force | at 29 or lower: avoid |
| Hydrochlorothiazide | no eGFR rule in force | at 29 or lower: ineffective; the registry suggests a loop diuretic instead |
| Glyburide | avoid (CKD stage 3 to 5) | none lower in the registry |
These rows restate our renal dosing registry, which summarises the drug labels. Check the current label and the indication; the prescriber makes the dose decision.
Drug Dosing Cutoffs at eGFR 35
3 drugs in our renal dosing registry have a label cutoff at 35.
Labels That Use Creatinine Clearance
These labels use Cockcroft-Gault creatinine clearance in mL/min, not eGFR. An eGFR of 35 does not mean a clearance of 35 mL/min, so calculate CrCl before applying them.
- Alendronate: CrCl below 35
- Atenolol: CrCl below 35
- Zoledronic Acid: CrCl below 35
The nearest other cutoffs are up at 40 (Piperacillin-Tazobactam, Sotalol) and down at 30 (28 drugs, listed under eGFR 30). Always confirm the current label, and leave the dose decision to the prescriber.
How a Result of 35 Is Confirmed
A result of 35 is confirmed by repeat testing over time, because one eGFR is a snapshot that can dip with dehydration or illness. Chronic kidney disease is diagnosed only when a low result, or kidney damage, lasts more than three months. Repeat testing, a urine albumin-to-creatinine ratio and, where muscle mass misleads, cystatin C confirm it.
When to Talk to Your Clinician
Ask for a review of an eGFR of 35 soon, particularly your medicine list, blood pressure and urine albumin. Follow-up is usually more frequent at this level. Seek timely advice for swelling, a marked drop in urine output or new breathlessness, and have kidney function rechecked before and after any scan that uses contrast dye.
Nearby eGFR Results
Or browse all eGFR results. For drug dosing, your clinician may use a creatinine clearance rather than eGFR (see CrCl vs eGFR).