Source: https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/implementation/

instrument implementation / implementation-contract

# Creatinine Clearance (Cockcroft-Gault) implementation

A source-bound implementation contract for Creatinine Clearance (Cockcroft-Gault); 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**: t4-002

**Effect**: Computation or source lookup only

## Input and validation requirements

A serum creatinine input of exactly zero produces division by zero, so the instrument must reject the input or return an explicit undefined result rather than a numeric clearance.

## 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": 50,
    "weight_kg": 70,
    "sex": "male",
    "serum_creatinine_mg_dL": 1
  },
  "expected_outputs": {
    "creatinine_clearance_mL_min": 87.5
  },
  "working": "140 − 50 = 90; 90 × 70 = 6300; female factor = 1.00; denominator = 72 × 1.0 = 72; CrCl = 6300 ÷ 72 = 87.5 mL/min."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/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`