eGFR (CKD-EPI 2021, race-free) implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t4-014

Effect

Computation or source lookup only

Input and validation requirements

A serum creatinine input of exactly 0 causes the negative power 0^(-0.302), producing an undefined or non-finite result. The instrument should reject this input instead of assigning an eGFR or CKD stage.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "age_years": 40,
    "sex": "male",
    "serum_creatinine_mg_dL": 0.9
  },
  "expected_outputs": {
    "eGFR_mL_min_1_73m2": 110.73,
    "stage_label": "G1"
  },
  "working": "Male: k = 0.9, alpha = -0.302. SCr/k = 0.9/0.9 = 1. Therefore min(1,1)^(-0.302) = 1 and max(1,1)^(-1.200) = 1. Age factor = 0.9938^40 = 0.77976. eGFR = 142 × 1 × 1 × 0.77976 = 110.73 mL/min/1.73 m². Since 110.73 >= 90, the eGFR category is G1."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json