Estimation of Creatinine Clearance

Use the Creatinine Clearance (CrCl) calculator in the GGC Medicines App or on the StaffNet Hub Clinical Info page (NHSGGC network access required) to calculate patient's CrCl. If it is not available then the following 'Cockcroft Gault' equation can be used to estimate CrCl.

CrCl (ml/minute) =	[140 – age (years)] x weight (kg)	x 1.23 (male) OR x 1.04 (female)
	serum creatinine (micromol/L)

Cautions!

Use the patient's actual body weight if their weight is less than or equal to their ideal body weight (IBW).
Use the patient's adjusted body weight if their weight is greater than their IBW.
Use 60micromol/L if the creatinine concentration is <60micromol/L.
This equation may overestimate CrCl in elderly or malnourished patients.
DO NOT USE eGFR.

Transgender patient

For transgender patients (following ≥6 months of hormonal gender affirming therapy or at any time after completion of gender affirming surgery) calculate CrCl and IBW according to the patient's gender identity (see the calculator within the GGC Medicines App or via the StaffNet Hub (link to page only active if connected to NHSGGC network).

If gender affirming therapy does not meet the criteria above, use the patient's sex at birth according to their electronic records. The second last digit of a CHI number informs of a patient's assigned sex at birth - for those assigned male it is odd and for those assigned female it is even.

Guideline reviewed: July 2024

Page updated: August 2024