نظرة سريرية عامة

Cockcroft-Gault creatinine clearance is a bedside decision-support calculation used to standardize a defined part of clinical assessment. It estimates unindexed creatinine clearance and remains referenced in many medication labels and renal-dose studies. The result should be interpreted with the patient’s presentation, baseline function, serial observations, laboratory method, medication exposure, and the protocol used by the treating institution. It is an aid to communication and risk stratification rather than an independent diagnosis or treatment order.

Enter contemporaneous values and confirm every unit before calculating. When physiology is changing, repeat assessment and prioritize the clinical trajectory over a single number. Document the input values alongside the result so another clinician can reproduce the calculation and recognize assumptions. Thresholds describe populations and do not remove the need to investigate discordant symptoms, examination findings, imaging, or biomarkers.

دواعي الاستخدام

• Renal-dose assessment when drug labeling uses Cockcroft-Gault CrCl
• Stable adult creatinine with known age and weight

القيود والسلامة

The equation predates standardized creatinine assays and can diverge from measured clearance or modern eGFR, especially at extremes of age and body composition. Validation cohorts, case mix, prevalence, and treatment era affect observed event rates. Pregnancy, extremes of age or body composition, critical illness, and major comorbidity may reduce transportability unless specifically represented in the original model. Do not extrapolate beyond the stated population or substitute this estimate for a validated local pathway.

Before acting, check for missing data, measurement error, competing diagnoses, contraindications, and time-sensitive emergencies. A low-risk label never overrides clinician concern; a high-risk label does not prove the target condition. Discuss consequential decisions with the appropriate senior or specialty team and use current regional guidance.

• Not validated in children, pregnancy, dialysis, or rapidly changing creatinine
• Weight selection at body-size extremes requires clinical judgment

المعادلة

CrCl = [(140 − age) × dosing weight] / (72 × Scr) × 0.85 if female. IBW male=50+2.3/inch >5 ft; female=45.5+2.3/inch; AdjBW=IBW+0.4(ABW−IBW)

تفسير النتائج

• ≥60 mL/min — Higher estimated clearance: Dose adjustment may still depend on the specific medicine. Use the drug label and clinical context.
• 30–59 — Reduced: Many renally cleared medicines require review. Check drug-specific dose and interval.
• <30 — Markedly reduced: Accumulation and toxicity risk may be substantial. Pharmacy/specialist review; check dialysis and AKI status.

المراجع

1. Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976.
2. Winter MA, et al. Impact of various body weights on Cockcroft-Gault.

الأسئلة الشائعة

Which weight should be used?

Follow the medication or institutional protocol. Actual weight is traditional; ideal or adjusted weight is often considered in obesity.

Can I enter µmol/L?

This version expects mg/dL. Convert µmol/L to mg/dL by dividing by 88.4.

Is CrCl the same as eGFR?

No. They use different equations and normalization; use the method validated for the decision.