eGFR, CKD-EPI 2021 creatinine equation (race-free)

Estimate the kidney filtering rate from creatinine, age and sex (2021 equation, no race term).

Rule and version: ckd_epi_2021@1.0
Published source: Inker LA, Eneanya ND, Coresh J, et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med 2021;385:1737-49. Equation as restated by the National Kidney Foundation (CKD-EPI Creatinine Equation, 2021). https://www.kidney.org/ckd-epi-creatinine-equation-2021
Edition: Inker et al., N Engl J Med 2021;385:1737-49 (2021 race-free eGFR equation)
Effective: from 2021-09-23
Role: primary equation for every eGFR on the screen
Status: draft: encoded from the published source; not yet signed off by a clinical reviewer
Clinical reviewer: —
Coding reviewer: —
Sponsor: none
Body hash: 2bc35edbf2f801a13194a537bb67b28d8c3b0175462b716b9f23c6c51f581517

Thresholds and parameters

{
  "age": "whole years at the collection date",
  "age_base": 0.9938,
  "alpha": {
    "F": -0.241,
    "M": -0.302
  },
  "exp_above": -1.2,
  "female_factor": 1.012,
  "formula": "eGFR = 142 x min(Scr/k, 1)^a x max(Scr/k, 1)^-1.200 x 0.9938^age x 1.012 [if female]",
  "intercept": 142,
  "kappa": {
    "F": 0.7,
    "M": 0.9
  },
  "loinc_creatinine": "2160-0",
  "report_decimals": 1,
  "unit": "mg/dL"
}

Boundary tests: 9/9 pass

pass · Scr 1.0 mg/dL, age 50, M: expected 91.69, got 91.69
pass · Scr 1.28 mg/dL, age 65, M: expected 62.11, got 62.11
pass · Scr 0.7 mg/dL, age 40, F: expected 112.05, got 112.05
pass · Scr 1.0 mg/dL, age 60, F: expected 64.5, got 64.50
pass · Scr 2.0 mg/dL, age 70, M: expected 35.24, got 35.24
pass · Scr 4.0 mg/dL, age 70, M: expected 15.34, got 15.34
pass · Scr 1.45 mg/dL, age 71, M: expected 51.5, got 51.52
pass · Scr 1.55 mg/dL, age 71, M: expected 47.6, got 47.56
pass · Scr 2.4 mg/dL, age 71, M: expected 28.1, got 28.14