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An eGFR calculator is a clinical tool that applies the CKD-EPI 2021 creatinine equation (eGFRcr) which is a validated, race-free mathematical equation used to convert a patient's IDMS-standardised serum creatinine (mg/dL), age, and sex into an estimated glomerular filtration rate expressed in mL/min/1.73 m² Calculate eGFR (CKD-EPI 2021) below:
Every summary carries citations with verbatim excerpts from the source, so you can open it, read it in context and confirm it says what the answer claims. What surfaces are decided by clinical quality, the governed alternative to pasting a clinical question into a general AI chatbot and hoping the answer holds.
Heidi Evidence draws on sources clinicians already trust, from Elsevier and DynaMed to MIMS Australia, and your organization can layer in its own regional pathways, policies, and formularies.
Heidi is the first in its field to hold ISO 42001 certification for AI management. Since Evidence is designed as a reference tool, the clinical call (and the responsibility for it) stays with you.
Evidence draws on the patient visit and its context, so the specifics travel with the question instead of being left behind. When a calculation is involved, the logic sits alongside the result, so you can see how it was reached and confirm it yourself rather than trust a black box.
Making that connection between the patient and the GP, like a puzzle fitting together.
Deborah Hawthorne
Clinicians at Connect2Care
Medical knowledge only. Not for autonomous decision making. Check sources and use your clinical judgement.
An eGFR calculator provides only half of the staging picture because KDIGO 2024 classifies CKD by cause, GFR category, and albuminuria category (CGA). CKD is diagnosed when either eGFR <60 mL/min/1.73 m² or uACR ≥30 mg/g persists for more than three months, and both measures together are used for staging and risk stratification.
For renin-angiotensin system inhibitors (ACEi or ARB), KDIGO 2024 recommendations are stratified: for non-diabetic CKD with severely increased albuminuria (A3, uACR >300 mg/g), starting an ACEi or ARB is recommended (1B); for non-diabetic CKD with moderately increased albuminuria (A2, uACR 30–300 mg/g), starting a RASi is suggested (2C weaker recommendation); for diabetic CKD with A2 or A3 albuminuria, starting a RASi is recommended regardless of blood pressure (1B). Regardless of indication, titrate to the maximum tolerated dose and avoid dual RAS blockade including direct renin inhibitors.
Statin recommendations from KDIGO apply across the eGFR spectrum in adults ≥50 not on dialysis: statin or statin/ezetimibe combination is recommended for eGFR <60 mL/min/1.73 m² (Grade 1A), and statin alone is recommended for eGFR ≥60 mL/min/1.73 m² (Grade 1B).
SGLT2 inhibitors should be initiated at eGFR ≥20 mL/min/1.73 m² in T2D with CKD (Grade 1A); for CKD without T2D, initiation is recommended at eGFR ≥20 with uACR ≥200 mg/g or with heart failure (Grade 1A), and suggested at eGFR 20-45 with uACR <200 mg/g (Grade 2B). Once initiated, it is reasonable to continue SGLT2i even if eGFR falls below 20, until kidney replacement therapy (KRT) is initiated; use in dialysis or transplant patients is generally not supported.
In type 2 diabetes with CKD, metformin is recommended when eGFR ≥30 mL/min/1.73 m². However, dose reduction should be considered when eGFR falls to 45-59, and the maximum daily dose should be halved when eGFR is 30-44 mL/min/1.73 m². Metformin should be discontinued when eGFR falls below 30 mL/min/1.73 m².
Refer to nephrology at eGFR <30 mL/min/1.73 m² (G4-G5), or when a validated Kidney Failure Risk Equation (KFRE) identifies a 5-year kidney failure risk ≥3–5%, or earlier for persistent uACR >300 mg/g, resistant hypertension, or refractory electrolyte abnormality.