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

instrument mechanism / verified-clean

# A1C to Estimated Average Glucose Converter mechanism

The inspectable method record for A1C to Estimated Average Glucose Converter, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The mg/dL formula is correct for the standard ADAG HbA1c-to-eAG relationship and the existing educational, not-medical-advice label is appropriate. Resolve the exact mmol/L conversion constant and define input validation and acceptable HbA1c bounds before release.

- The formula eAG(mg/dL)=28.7×A1C−46.7 is the standard ADAG relationship for HbA1c reported in percent and eAG reported in mg/dL.

- No formula or conversion constant is specified for the claimed mmol/L output. The implementation must explicitly define whether it divides mg/dL by 18.0 or by the more precise glucose conversion factor 18.0182.

- No valid-input constraint is specified. HbA1c must be numeric and within a clinically meaningful range; unrestricted values can produce nonsensical or negative eAG results.

## Units and conventions

- HbA1c is expressed as percent, for example 5.7% represented numerically as 5.7, not 0.057.

- The supplied ADAG formula produces eAG in mg/dL.

- For these test vectors, mmol/L is calculated as eAG(mg/dL)÷18.0, a common clinical approximation; using 18.0182 would produce slightly different mmol/L values.

- Outputs shown in mmol/L are rounded to two decimal places; mg/dL values are shown to one or two decimal places as appropriate.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "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."
}
````

## Failure boundary

- 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.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/a1c-to-estimated-average-glucose-converter/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/a1c-to-estimated-average-glucose-converter/implementation/>)[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`