What is the formula for calculating the WPI

Formula collection

Kidney: GFR according to the CKD-EPI formula (Chronic Kidney Disease Epidemiology Collaboration)

In addition to the creatinine clearance, the calculation of the glomerular filtration rate (GFR) after measuring the serum creatinine alone is becoming increasingly important due to its simpler handling.

In view of several extrarenal influences on the creatinine concentration in serum, this calculation can only be interpreted as an estimate of the GFR. In addition, due to the so-called creatinine-blind area, it only recognizes significant kidney dysfunction, since the serum concentration of creatinine only exceeds the reference range when the GFR is about 50 percent reduced.

Thus, neither the isolated determination of creatinine in the serum nor the calculation of the GFR on the basis of the serum creatinine concentration is suitable to indicate kidney disease in the early stages. The calculation of the endogenous creatinine clearance (see there) is preferable in these cases.

The so-called "simplified MDRD formula", which is often routinely used to calculate the GFR, is not very precise and underestimates the GFR in the higher range> 60 ml / min / 1.73m².

We are therefore now using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) as the basis for calculation. This formula was developed by a working group at the NIDDKD (National Institute of Diabetes and Digestive and Kidney Disease, Bethesda / MD, USA) on the basis of 8,254 patients. The formula was validated on a further collective of 3,896 participants. The formula shows a better agreement with reference methods than the MDRD formula, especially in the critical area. This formula has not been evaluated on patients> 70 years of age. The results obtained are extrapolated.

Reference areas (ml / min / 1.73 m²)

AgeWomenMen
18 - 2972 - 10094 - 140
30 - 3971 - 12159 - 137
40 - 4950 - 10276 - 120
50 - 5950 - 9867 - 109
60 - 6945 - 7554 - 98
70 - 7937 - 6149 - 79
from 8027 - 5530 - 60

rating

Degree of renal insufficiencyGFR (ml / min)Clinical picture
I.>90Normal results
II60-89Slight functional kidney damage
III30-59Moderate functional kidney damage
IV15-29Severe functional kidney damage
V.<15Kidney failure

Literature:
Levey AS et al. for the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) A New Equation to Estimate Glomerular Filtration Rate. Ann Intern Med. 2009; 150: 604-612