eGFR (CKD-EPI 2021)
Estimates GFR using race-free CKD-EPI 2021 creatinine equation. Defines CKD staging.
How to use & interpret
eGFR estimates kidney filtering function from serum creatinine, age and sex (the CKD-EPI 2021 equation is the current UK standard), reported as mL/min/1.73m². It is used to detect and stage chronic kidney disease and to guide many drug doses.
Stage by eGFR with KDIGO categories G1–G5 (≥90, 60–89, 45–59, 30–44, 15–29, <15), always alongside albuminuria, because eGFR alone does not capture kidney damage. eGFR assumes a steady state, so it is unreliable in acute kidney injury, at extremes of muscle mass or body size, and in pregnancy — in those situations, and for narrow-therapeutic-index drug dosing, use measured or Cockcroft–Gault creatinine clearance.
Score interpretation
eGFR ≥90 ml/min/1.73m²: CKD G1 (normal or high). CKD only if other markers present (proteinuria, haematuria).
→ Monitor annually if other CKD markers. No treatment required for eGFR alone.
eGFR 60–89: CKD G2. Mildly decreased. Normal for age in elderly patients.
→ Monitor 6–12 monthly. Control BP (target <130/80 mmHg). Avoid nephrotoxins. Check for proteinuria.
eGFR 45–59: CKD G3a. Moderate CKD.
→ Nephrology referral if falling. Review medications. Avoid NSAIDS. Monitor Ca, PO₄, PTH, Hb. Control BP. CV risk reduction.
eGFR 30–44: CKD G3b. Advanced moderate CKD.
→ Nephrology referral. Dose-adjust renally cleared drugs (e.g. metformin stop < 30, SGLT2i stop < 30–45). Anaemia management. Bone protection.
eGFR 15–29: CKD G4. Severe reduction.
→ Nephrology. Prepare for renal replacement therapy (RRT) — educate on options: HD, PD, transplant. AV fistula creation. Vaccinations (Hep B, flu, pneumococcal).
eGFR < 15: CKD G5. Kidney failure.
→ RRT planning (dialysis or transplant). Conservative management discussion if appropriate. Urgent nephrology.
Interpretation bands for the eGFR. Apply clinical judgement and local guidance.
Frequently asked questions
Should I use eGFR or creatinine clearance for drug dosing?
Most modern dosing uses eGFR (CKD-EPI). However, some drugs (e.g. DOACs, aminoglycosides, and dosing at extremes of weight) are validated against absolute Cockcroft–Gault creatinine clearance — check the specific drug's formulary entry.
Why is my reported eGFR capped at 90?
Many labs report values above 90 simply as '≥90' because the equation is less precise in the normal range; small changes there are rarely clinically meaningful.
References
- Inker LA et al. New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. N Engl J Med. 2021.
- KDIGO 2024 CKD Guideline.
Related
Curated clinical cross-links plus same-class fallbacks.
- Methotrexate (Dermatology — Psoriasis) · Disease-Modifying Antirheumatic / Immunosuppressant
- Cetuximab · Anti-EGFR Monoclonal Antibody — Head and Neck Cancer
- Acetazolamide (Ménière's Disease) · Carbonic Anhydrase Inhibitor (Diuretic)
- Zinc acetate · Zinc salt (Wilson's disease)
- Sulfasalazine · Aminosalicylate / Disease-Modifying Antirheumatic Drug (DMARD)
- Hydroxycarbamide (Hydroxyurea) · Cytoreductive agent / Sickle cell disease / CML
- Sepsis Screening and Sepsis Six · UK Sepsis Trust; NICE NG51; Surviving Sepsis Campaign 2021
- Unintentional Weight Loss Workup · NICE NG12; BSG
- Chronic Fatigue Workup · NICE NG206; BMJ Best Practice
- Lymphadenopathy Workup · NICE NG12; BMJ Best Practice
- Pre-op Medical Clearance · NICE NG45; ESC 2022
- Secondary Hypertension Workup · NICE NG136; ESH 2023
Featured in these MRCEM clinical pathways
The eGFR is covered in detail — with RCEM/NICE evidence base, indications and pitfalls — in the following exam-focused pathways on our sister siteReviseMRCEM.
MRCEM Primary / Intermediate / OSCE candidates: each pathway includes exam-style questions, RCEM/NICE citations, and FAQ summaries.
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.