Source: https://guthlabs.ai/docs/instruments/a1c-to-estimated-average-glucose-converter/implementation/

instrument implementation / implementation-contract

# A1C to Estimated Average Glucose Converter implementation

A source-bound implementation contract for A1C to Estimated Average Glucose Converter; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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

[01**Overview**](<https://guthlabs.ai/docs/instruments/a1c-to-estimated-average-glucose-converter/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/a1c-to-estimated-average-glucose-converter/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/a1c-to-estimated-average-glucose-converter/qualification/>)

## 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`