Source: https://guthlabs.ai/docs/instruments/anion-gap-calculator/mechanism/

instrument mechanism / verified-clean

# Anion Gap Calculator mechanism

The inspectable method record for Anion Gap Calculator, kept separate from implementation and qualification.

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

## Model scope

The arithmetic formula is correct for the claimed potassium-excluded anion gap. Keep the supplied educational-only, not-medical-advice label prominent. Resolve the exact normal-range endpoint convention and the handling of lab-specific ranges before release.

- AG=Na−(Cl+HCO3) is the standard potassium-excluded anion-gap formula when all inputs are in consistent units.

- The normal-range flag is underspecified: it does not state whether the 8 and 16 mmol/L endpoints are inclusive, and it does not provide a mechanism for lab-specific reference ranges.

- The specification does not state whether HCO3 means measured serum bicarbonate or BMP total CO2, which is usually used as its clinical proxy.

## Units and conventions

- Na, Cl, and HCO3 must all be supplied in mmol/L; do not mix mmol/L with other units.

- For these monovalent ions, mmol/L and mEq/L have the same numerical values.

- The stated reference interval is assumed to be 8-16 mmol/L and inclusive for the test vectors only.

- No potassium term is included; this is the conventional potassium-excluded anion gap.

- Albumin correction is not performed, so the result is an uncorrected anion gap.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "Na": 140,
    "Cl": 104,
    "HCO3": 24,
    "units": "mmol/L"
  },
  "expected_outputs": {
    "anion_gap": 12,
    "anion_gap_units": "mmol/L",
    "normal_range_flag": true
  },
  "working": "AG = Na − (Cl + HCO3) = 140 − (104 + 24) = 140 − 128 = 12 mmol/L. Since 8 ≤ 12 ≤ 16, the normal-range flag is true."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

Extreme finite inputs overflow during Cl + HCO3, producing Infinity and then an anion gap of -Infinity. The calculator should detect overflow or reject the result instead of treating it as a meaningful value.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/anion-gap-calculator/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/anion-gap-calculator/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/anion-gap-calculator/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-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`