eGFR 50: What It Means (CKD Stage G3a)
An eGFR of 50 mL/min/1.73m² is KDIGO category G3a (45 to 59). 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 50 mL/min/1.73m² falls in KDIGO category G3a (45 to 59), which means mildly to moderately decreased filtration. At age 50 it matches a creatinine of about 1.66 mg/dL in a man and 1.30 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 50 Sits Within G3a
An eGFR of 50 is 5 points above the G3a floor of 45. It is 10 points below the G2 line at 60. The KDIGO categories run from G1 to G5; G3a is explained in more depth on the CKD stage 3 page.
G3a is mildly to moderately decreased filtration. If it lasts more than three months it meets the definition of chronic kidney disease on its own, even without albuminuria. Most people have no symptoms at this level; care usually centres on blood pressure, blood glucose, a urine albumin test and a review of medicines.
What Creatinine Gives an eGFR of 50?
The creatinine behind an eGFR of 50 comes from solving the race-free CKD-EPI 2021 equation backwards, by age and sex:
| Age | Man | Woman |
|---|---|---|
| 30 | 1.84 mg/dL (163 µmol/L) | 1.44 mg/dL (128 µmol/L) |
| 40 | 1.75 mg/dL (154 µmol/L) | 1.37 mg/dL (121 µmol/L) |
| 50 | 1.66 mg/dL (147 µmol/L) | 1.30 mg/dL (115 µmol/L) |
| 60 | 1.57 mg/dL (139 µmol/L) | 1.24 mg/dL (109 µmol/L) |
| 70 | 1.49 mg/dL (132 µmol/L) | 1.17 mg/dL (104 µmol/L) |
| 85 | 1.38 mg/dL (122 µmol/L) | 1.09 mg/dL (96 µmol/L) |
A 30-year-old man reaches 50 at 1.84 mg/dL, while an 85-year-old woman reaches it at 1.09 mg/dL. The older the person, the lower the creatinine behind the same eGFR. Nearby creatinine guides: creatinine 1.2 mg/dL (106 µmol/L), creatinine 1.3 mg/dL (115 µmol/L), creatinine 1.4 mg/dL (124 µmol/L), creatinine 1.5 mg/dL (133 µmol/L), creatinine 1.6 mg/dL (141 µmol/L).
eGFR 50 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 50, the absolute values are:
| Example adult | BSA (m²) | Absolute GFR (mL/min) |
|---|---|---|
| Man, 40, 178 cm, 80 kg | 1.99 | 57 |
| Woman, 65, 163 cm, 62 kg | 1.67 | 48 |
| Woman, 82, 157 cm, 48 kg | 1.45 | 42 |
| Man, 55, 175 cm, 118 kg | 2.40 | 69 |
What Changes at an eGFR of 50
50 is 20 points above 30, and a fall of about 42% would cross that line. Below 30, KDIGO advises sharing care with a kidney specialist (nephrologist). It is already below 60.
1 of the 9 medicines in our registry whose labels use eGFR have a rule in force at 50. No eGFR-based rule in the registry starts between 55 and 50.
| Medicine | At eGFR 50 | Next change if eGFR falls |
|---|---|---|
| Metformin | no eGFR rule in force | at 45 or lower: not to be started; the registry advises halving an existing dose |
| Sitagliptin | no eGFR rule in force | at 44 or lower: dose lowered to 50 mg |
| Saxagliptin | no eGFR rule in force | at 45 or lower: dose lowered to 2.5 mg |
| Dapagliflozin | no eGFR rule in force | at 44 or lower: glucose-lowering effect limited |
| 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 50
16 drugs in our renal dosing registry have a label cutoff at 50.
Labels That Use Creatinine Clearance
These labels use Cockcroft-Gault creatinine clearance in mL/min, not eGFR. An eGFR of 50 does not mean a clearance of 50 mL/min, so calculate CrCl before applying them.
- Cefazolin: CrCl below 50
- Ceftazidime: CrCl below 50
- Ciprofloxacin: CrCl below 50
- Codeine: CrCl below 50
- Edoxaban: CrCl 15 to 50
- Entecavir: CrCl below 50
- Famotidine: CrCl below 50
- Fluconazole: CrCl below 50
- Fondaparinux: CrCl 30 to 50
- Levofloxacin: CrCl below 50
- Meropenem: CrCl below 50
- Morphine: CrCl below 50
- Ofloxacin: CrCl below 50
- Rivaroxaban: CrCl 15 to 50
- Tenofovir DF: CrCl below 50
- Valacyclovir: CrCl below 50
The nearest other cutoffs are up at 60 (9 drugs, listed under eGFR 60) and down at 45 (4 drugs, listed under eGFR 45). Always confirm the current label, and leave the dose decision to the prescriber.
How a Result of 50 Is Confirmed
A result of 50 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
Bring an eGFR of 50 to your next appointment rather than waiting for symptoms. A repeat test in about three months, a urine albumin check and a medication review are the usual next steps. 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).