Nigeria
Kidney function test: creatinine, eGFR and what the stages mean
A kidney function test usually means serum creatinine, sometimes with urea and electrolytes. Creatinine alone is hard to interpret — it depends on muscle mass — so it is converted into an estimated glomerular filtration rate (eGFR), which is what the stages below refer to.
KDIGO eGFR stages (mL/min/1.73m²)
| Stage | eGFR | Meaning |
|---|---|---|
| G1 | 90 and above | Normal function |
| G2 | 60 – 89 | Mildly reduced |
| G3a | 45 – 59 | Mild to moderate reduction |
| G3b | 30 – 44 | Moderate to severe reduction |
| G4 | 15 – 29 | Severely reduced |
| G5 | Below 15 | Kidney failure |
CKD-EPI 2021 is the current equation
The 2021 CKD-EPI creatinine equation removed the race coefficient used by older formulas. If a result was calculated years ago with an older equation, the eGFR is not directly comparable. Vitals uses the 2021 equation throughout.
Medications that quietly damage kidneys
Long-term NSAIDs — diclofenac, ibuprofen, the combination sachets sold widely without prescription — are a leading avoidable cause of reduced kidney function. Aminoglycoside antibiotics, some herbal preparations and contrast dye add to it. Metformin dosing must also be adjusted below certain eGFR levels. The medication checker flags these against your own eGFR.
Who should be tested
Anyone with diabetes or hypertension, at least yearly. Anyone taking NSAIDs regularly. Anyone with a family history of kidney disease. Early chronic kidney disease has no symptoms at all, which is precisely why it is a screening test.
Track the trend, not one value
A single eGFR is noisy. The direction across repeat tests is what matters clinically, so log each creatinine result and the trend chart will show whether function is stable, improving or declining — plus a one-page summary of questions to ask your clinician.
Keep reading
Educational only. Reference ranges are general guidance and are not a diagnosis — take your results to a qualified clinician.
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