{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"egfr"},"result":{"entity_type":"calculator","id":"egfr","calculator_id":"egfr","canonical_url":"https://tttkmbb.com/medical/egfr","name":"eGFR Calculator","title":"eGFR Calculator – CKD-EPI 2021 Race-Free Creatinine Equation with KDIGO Stage","category":"medical","category_name":"Medical & Clinical","tool_name":"calculate_egfr","featured_mcp_tool":false,"description":"Estimates glomerular filtration rate from serum creatinine, age and sex with the CKD-EPI 2021 race-free creatinine equation, and assigns the KDIGO GFR category (G1–G5).","use_when":"You have an adult's serum creatinine (mg/dL or µmol/L), age and sex and need an eGFR in mL/min/1.73 m² or its CKD stage.","do_not_use_when":"The person is under 18 (paediatric equations differ), creatinine is not in steady state (acute kidney injury), or you need drug-dosing clearance in mL/min (use creatinine-clearance).","inputs":[{"name":"creatinine","label":"Serum creatinine","type":"number","required":true,"max":4000,"exclusive_min":0,"description":"Serum creatinine in the unit given by creatinine_unit.","example":1.2},{"name":"creatinine_unit","label":"Creatinine unit","type":"enum","required":false,"default":"mg_dl","values":[{"value":"mg_dl","label":"mg/dL","aliases":["mg/dl","mgdl"]},{"value":"umol_l","label":"µmol/L","aliases":["umol/l","µmol/l","micromol/l","umol","mcmol/l"]}],"description":"Unit of the serum creatinine value (1 mg/dL = 88.4 µmol/L).","example":"mg_dl"},{"name":"age_years","label":"Age","type":"number","unit":"years","required":true,"min":18,"max":120,"description":"Age in years (adults only).","example":55},{"name":"sex","label":"Sex","type":"enum","required":true,"values":[{"value":"male","label":"Male","aliases":["m","man"]},{"value":"female","label":"Female","aliases":["f","woman"]}],"description":"Sex used to select the formula coefficients or thresholds.","example":"female"}],"outputs":[{"name":"egfr_ml_min_1_73m2","label":"eGFR","type":"number","unit":"mL/min/1.73 m²","decimals":1,"description":"Estimated GFR by CKD-EPI 2021 (creatinine), indexed to 1.73 m² body surface area."},{"name":"ckd_stage","label":"KDIGO GFR category","type":"string","decimals":4,"description":"G1 ≥90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15 mL/min/1.73 m²."},{"name":"stage_description","label":"Stage description","type":"string","decimals":4,"description":"KDIGO wording for the GFR category."},{"name":"creatinine_mg_dl","label":"Creatinine","type":"number","unit":"mg/dL","decimals":2,"description":"Creatinine used in the equation, in mg/dL."},{"name":"creatinine_umol_l","label":"Creatinine","type":"number","unit":"µmol/L","decimals":0,"description":"Same creatinine in µmol/L (× 88.4)."}],"input_schema":{"type":"object","properties":{"creatinine":{"description":"Serum creatinine in the unit given by creatinine_unit.","type":"number","maximum":4000,"exclusiveMinimum":0,"examples":[1.2]},"creatinine_unit":{"description":"Unit of the serum creatinine value (1 mg/dL = 88.4 µmol/L).","type":"string","enum":["mg_dl","umol_l"],"default":"mg_dl","examples":["mg_dl"]},"age_years":{"description":"Age in years (adults only). Unit: years.","type":"number","minimum":18,"maximum":120,"examples":[55],"x-unit":"years"},"sex":{"description":"Sex used to select the formula coefficients or thresholds.","type":"string","enum":["male","female"],"examples":["female"]}},"additionalProperties":false,"required":["creatinine","age_years","sex"]},"output_schema":{"type":"object","properties":{"egfr_ml_min_1_73m2":{"description":"Estimated GFR by CKD-EPI 2021 (creatinine), indexed to 1.73 m² body surface area. Unit: mL/min/1.73 m².","type":"number","x-unit":"mL/min/1.73 m²"},"ckd_stage":{"description":"G1 ≥90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15 mL/min/1.73 m².","type":"string"},"stage_description":{"description":"KDIGO wording for the GFR category.","type":"string"},"creatinine_mg_dl":{"description":"Creatinine used in the equation, in mg/dL. Unit: mg/dL.","type":"number","x-unit":"mg/dL"},"creatinine_umol_l":{"description":"Same creatinine in µmol/L (× 88.4). Unit: µmol/L.","type":"number","x-unit":"µmol/L"}}},"formula":"eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age_years × 1.012 (if female); κ = 0.7 (female) / 0.9 (male); α = −0.241 (female) / −0.302 (male); Scr in mg/dL (µmol/L ÷ 88.4)","method":"CKD-EPI 2021 removes the race coefficient of the 2009 equation; a CKD stage requires the eGFR to persist for more than 3 months and is less reliable at extremes of muscle mass, in pregnancy or with unstable creatinine. Results are informational only and not a substitute for clinical judgement or medical advice.","sources":[{"name":"National Kidney Foundation – CKD-EPI Creatinine Equation (2021)","url":"https://www.kidney.org/professionals/ckd-epi-creatinine-equation-2021","type":"standard","retrieved_at":"2026-09-24"},{"name":"Inker LA et al. (2021) New creatinine- and cystatin C-based equations to estimate GFR without race, N Engl J Med 385:1737-1749","url":"https://pubmed.ncbi.nlm.nih.gov/34554658/","type":"peer_reviewed","retrieved_at":"2026-09-24"},{"name":"NIDDK – Estimated Glomerular Filtration Rate Calculators","url":"https://www.niddk.nih.gov/health-information/professionals/clinical-tools-patient-management/kidney-disease/laboratory-evaluation/estimated-gfr-calculators","type":"government","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"Female, 55 years, creatinine 1.2 mg/dL","inputs":{"creatinine":1.2,"creatinine_unit":"mg_dl","age_years":55,"sex":"female"},"expected":{"egfr_ml_min_1_73m2":53.5,"ckd_stage":"G3a","creatinine_umol_l":106},"url":"https://tttkmbb.com/api/v1/calculate/egfr?creatinine=1.2&creatinine_unit=mg_dl&age_years=55&sex=female"},{"name":"Male, 40 years, creatinine 0.9 mg/dL","inputs":{"creatinine":0.9,"age_years":40,"sex":"male"},"expected":{"egfr_ml_min_1_73m2":110.7,"ckd_stage":"G1"},"url":"https://tttkmbb.com/api/v1/calculate/egfr?creatinine=0.9&age_years=40&sex=male"},{"name":"Female, 70 years, creatinine 106 µmol/L","inputs":{"creatinine":106,"creatinine_unit":"umol_l","age_years":70,"sex":"female"},"expected":{"egfr_ml_min_1_73m2":48.7,"ckd_stage":"G3a","creatinine_mg_dl":1.2},"url":"https://tttkmbb.com/api/v1/calculate/egfr?creatinine=106&creatinine_unit=umol_l&age_years=70&sex=female"}],"faq":[{"q":"Why does the result differ from an older lab report?","a":"Reports before 2021–2022 often used the CKD-EPI 2009 or MDRD equations with a race coefficient; the 2021 equation gives somewhat higher values for Black adults and slightly lower values for others."},{"q":"Can I use it for drug dosing?","a":"Most dosing tables are based on Cockcroft-Gault creatinine clearance in mL/min, not BSA-indexed eGFR; use creatinine-clearance, or de-index eGFR by multiplying by BSA/1.73."}],"tags":["egfr","gfr","ckd-epi 2021","kidney function","creatinine","ckd stage"],"related":[{"calculator_id":"creatinine-clearance","reason":"Cockcroft-Gault clearance in mL/min for drug dosing."},{"calculator_id":"body-surface-area","reason":"De-index eGFR to the person's actual BSA."}],"links":{"html":"https://tttkmbb.com/medical/egfr","markdown":"https://tttkmbb.com/medical/egfr.md","json":"https://tttkmbb.com/medical/egfr.json","api":"https://tttkmbb.com/api/v1/calculate/egfr","schema":"https://tttkmbb.com/api/v1/calculators/egfr","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:45:53Z","next_actions":[{"tool":"run_calculator","calculator_id":"egfr","reason":"Run eGFR Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/medical/egfr.md"}}