eGFR

 

Alternative names, keywords

Estimated glomerular filtration rate

Samples required

● Clotted blood (gold cap, 5 mL tube). Smaller tubes are available for paediatric samples.

Best taken more than 12h after eating meat (NICE clinical guidelines CG73 Chronic kidney disease).

Blood samples received more than 8 hours after venepuncture are unsuitable for creatinine analysis.

Test indications

Estimation of GFR from serum creatinine. Click here for the full UK CKD Guidelines.

Test information

Estimated GFR (MDRD) equation

eGFR = 175 x (serum creatinine)-1.154 x (age)-0.203 x (0.742 if female)

This equation should not be used in patients with near normal function, as its accuracy is not validated at this level. As a result any sample with a serum creatinine in the normal range will simply be reported as 'eGFR ≥60 ml/min/1.73m2 ', as will any mildly elevated serum creatinine result where the eGFR calculates to a value that is ≥60 ml/min/1.73m2.

Factors affecting test performance/ results

See creatinine (serum).

Results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.

Reference range

≥ 60 mL/ min/ 1.73m2

  • The eGFR should not be used for patients with acute renal impairment, in which situation the serum creatinine is changing rapidly and the equation is not validated. A message will be attached to the report as a reminder.
  • The equation is not validated in children, and will not be reported in individuals under the age of 18.
  • Reduced muscle mass (e.g. in malnourished, amputees, muscle-wasting diseases) will lead to overestimation and increased muscle mass (e.g. bodybuilding) to underestimation of the GFR.
  • The equation is not validated in pregnant women.

Turnaround time

Same day (within 1h if urgent)

Enquiries

Biochemistry (Automation)

 

Details