A1C to Estimated Average Glucose Converter 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

t5-098

Effect

Computation or source lookup only

Input and validation requirements

• Missing mmol/L conversion specification creates an implementation and expected-output ambiguity.
• Non-numeric, missing, negative, or implausibly large HbA1c inputs are not constrained or validated.
• The formula can return a negative eAG for sufficiently low inputs; for example, A1c=0 gives 28.7×0−46.7=−46.7 mg/dL, which is physiologically nonsensical.
• The ADAG relationship is an estimate and depends on HbA1c assay/reporting conventions; it should not be presented as an individual patient's measured average glucose.
• If mmol/L conversion is implemented by division, the conversion denominator must be a fixed nonzero constant.

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": {
    "HbA1c_percent": 4
  },
  "expected_outputs": {
    "eAG_mg_dL": 68.1,
    "eAG_mmol_L": 3.78
  },
  "working": "28.7×4.0=114.8; 114.8−46.7=68.1 mg/dL; 68.1÷18.0=3.783333... mmol/L; rounded=3.78 mmol/L. This is a lower-boundary-ish, unit-conversion case."
}

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-tranche5/tranche5-results.json