Creatinine Clearance (Cockcroft-Gault) mechanism

Model scope

NEEDS_REVIEW because the exact weight convention and the allowed/meaningful sex categories are ambiguous. The educational, not-medical-advice label is appropriate, but the interface should also explicitly distinguish estimated Cockcroft-Gault creatinine clearance from eGFR and enforce positive SCr, positive weight, and valid age constraints.

• The algebraic formula is the standard Cockcroft-Gault form when age is in years, weight is in kg, and serum creatinine is in mg/dL.
• The weight definition is unspecified: actual body weight, ideal body weight, or adjusted body weight may be selected clinically depending on body composition and institutional dosing policy.
• The sex adjustment is represented only as a binary 0.85 multiplier; the applicable sex category and handling of patients who do not fit that binary input are unspecified.
• The formula does not state an applicable age range or constraints for physiologically valid inputs.

Units and conventions

• Age is measured in completed years.
• Weight is measured in kilograms.
• Serum creatinine (SCr) is measured in mg/dL; a value reported in µmol/L must be divided by 88.4 before use.
• The resulting CrCl is reported in mL/min without automatic normalization to body-surface area.
• The 0.85 multiplier is applied for female input and 1.00 otherwise, subject to the sex-category ambiguity noted above.

Inspectable vector

One of 4 source-bound review vectors:

{
  "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."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

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.

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-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json