Risk guide

eGFR and CKD-EPI 2021: reading your kidney numbers

Estimated glomerular filtration rate (eGFR) is the standard measure of kidney function. The 2021 CKD-EPI creatinine equation is the current recommended formula, and unlike its predecessor it does not use a race coefficient.

What it needs

  • Serum creatinine
  • Age and sex
  • Urine albumin-to-creatinine ratio, when available, for the KDIGO grid

How to read the result

eGFR is reported in mL/min/1.73m². G1 is 90 and above, G2 is 60-89, G3a is 45-59, G3b is 30-44, G4 is 15-29 and G5 is below 15. A single reduced value is not chronic kidney disease — the definition requires the abnormality to persist for at least three months.

Albuminuria matters as much as eGFR

The KDIGO heat map combines eGFR stage with albuminuria category. Someone with a mildly reduced eGFR but heavy albuminuria can sit in a higher risk box than someone with a lower eGFR and no protein leak.

Medication review

Reduced kidney function changes the safety and dosing of common drugs — NSAIDs, metformin, some antibiotics, contrast agents and several blood-pressure medicines. Vitals flags kidney-impacting entries from your medication list and generates a summary you can hand to a clinician.

Source

Inker LA et al., New England Journal of Medicine 2021;385:1737-1749

This guide is educational. It is not a diagnosis and does not replace a conversation with a qualified clinician.

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