# Nephrology Question 5 Instructor

Using the Cockcroft-Gault and MDRD formulas, calculate the estimated glomerular filtration rate (eGFR) in the following patient:

A 70 year old Caucasian male with serum creatinine 250 micromol/L and weight of 70kg. BUN and albumin are unavailable.

In which populations and at what GFRs do these estimation formula perform poorly?

Cockcroft Gault creatinine clearance is 24.1 ml/min. MDRD estimated GFR is 23.7 ml/min.

The Cochcroft-Gault formula is:

Creatinine clearance
= (140-age[years]) * weight [kg]
—————————-
(72 X serum creatinine)

For women, multiply by 0.85.

The abbreviated MRDRD formula:

GFR = 186.3 * (SCR)-1.154 * (age in years)-0.203 * 1.212 (if patient is black) * 0.742 (if female)

The CKD-EPI has been developed to be a more accurate tool to estimate GFR. It performs particularly well when GFR is relatively preserved.

MDRD and CKD-EPI eGFR can be calculated at:
http://www.qxmd.com/calculate-online/nephrology/mdrd-egfr
http://www.qxmd.com/calculate-online/nephrology/ckd-epi-egfr

iPhone, iPad, BlackBerry and Android users can get an eGFR calculator at
http://www.qxmd.com/apps/calculate-by-qxmd

These formula may not be reliable in pregnant women, children, or patients with normal renal function, obesity,or prior amputations.

References:

Cockcroft DW and Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976; 16(1): 31-41.

Levey et al. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Ann Intern Med. 1999; 130(6):461-70.

Levey AS, Stevens LA, Schmid CH, Zhang YL, Castro AF 3rd, Feldman HI, Kusek JW, Eggers P, Van Lente F, Greene T, Coresh J; CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration). A New Equation to Estimate Glomerular Filtration Rate. Ann Intern Med 150(9):604-12. (2009)