Estimation of Glomerular Filtration Rate (eGFR)
• As of 31/10/2005, a value of eGFR will be included on reports where serum creatinine is requested on patients 18 years and over, as recommended in the Position Statement of the Australasian Creatinine Consensus Working Group – Medical Journal of Australia 2005; [183 (3): 138-141].• Conditions where use of the MDRD formula is NOT appropriate for GFR estimation include but are not limited to the following:1. Subjects under 18 years of age.
2. Individuals of Aboriginal and Torres Strait Islander or Asian descent.
3. Extremes of body size.
4. Exceptional dietary intake, e.g. vegetarian or high protein diet.
5. For the purpose of determining drug dosage.
6. Rapidly changing renal function or patients on renal dialysis.
7. Severe renal disease.
8. Pregnancy• Where the estimation of GFR is required in the groups described above an alternative method for estimating kidney function should be performed,
[e.g Cockcroft and Gault formula for drug dosing].
Guide to Interpretation
eGFR = 60 mls/minute/1.73m2 does not necessarily exclude kidney disease.eGFR 30-59 mls/minute/1.73m2 suggests moderate chronic kidney disease and indicates the need for further investigation including assessment of proteinuria and cardiovascular risk factors.eGFR <30 mls/minute/1.73m2 usually suggests chronic kidney failure.The well known age – related decline in renal function has not been used in recommended responses to lower eGFR results as it is thought that this change may reflect the effects of disease rather than ageing itself. In elderly patients where life expectancy is unlikely to be limited by progressive renal disease further investigations of reduced eGFR is unlikely to be of benefit. In the United States mean eGFR for people aged 70 years and over has been calculated to be 75 mls/minute/1.73m2.Other considerations in interpretation include rate of change of eGFR and the presence of risk factors such as Diabetes Mellitus or hypertension.References : Medical Journal of Australia 2005; [183 (3): 117-118]
Medical Journal of Australia 2005; [183 (3): 138-141]
www.kidney.org.au