Wright GFR Equation Calculator

About the Wright Equation

GFR is the gold standard for the evaluation of kidney function but its actual measurement is difficult to perform in routine practice therefore, an estimation based on formulas that employ patient’s clinical data is often used.

The Wright equation provides one of those ways that estimate the glomerular filtration rate, as measure of renal function, based on the patient’s age, gender, measured serum creatinine and body surface area (by DuBois’ formula – from height and weight).

Developed in 2001, the Wright formula is particularly recognized as the most accurate and least biased formula for the estimation of GFR in elderly patients with a GFR >50 ml/min.

GFR (ml/min) = ((6580 – (38.8 × Age)) × BSA × (1 – (0.168 × Sex)))/SCr

Where:

• Gender value is 0 for men and 1 for women;
• BSA DuBois’s formula = 0.007184 x (Height in cm)725 x (Weight in kg)0.425
• Serum creatinine is expressed in µmol/L. In case the serum creatinine is given in mg/dL, the conversion from mg/dL to µmol/L is: 1 mg/dL = 88.4 µmol/L.

The Wright equation, similar to the Jelliffe one, does not require a patient's height or weight because it describes unstable renal function normalized to a body surface area of 1.73 m².

In the general population, it was observed that GFR declines steadily with aging, approximately 38% of elderly adults (70+) have an estimated glomerular filtration rate (eGFR) < 60 ml/min, with most having moderate reductions in eGFR in the 30-59 ml/min range.

Lower eGFR levels are associated with risk for adverse events such as cardiovascular disease (CVD), mortality, and end-stage renal disease (ESRD).

Other ways of estimating creatinine clearance or glomerular filtration rate to evaluate renal function include:

• The Cockcroft-Gault formula (gold standard);
• The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI);
• The Modification of Diet in Renal Disease (MDRD equation) studied in patients with renal dysfunction and GFR < 60 mL/min/1.73 m²;
• The Jelliffe equation.

References

Original reference

Wright JG, Boddy AV, Highley M, Fenwick J, McGill A, Calvert AH. Estimation of glomerular filtration rate in cancer patients. Br J Cancer. 2001; 84(4):452-9.

Other references

Marx GM, Blake GM, Galani E, Steer CB, Harper SE, Adamson KL, Bailey DL, Harper PG. Evaluation of the Cockroft-Gault, Jelliffe and Wright formulae in estimating renal function in elderly cancer patients. Ann Oncol. 2004; 15(2):291-5.

DuBois D, DuBois DF. A formula to estimate the approximate surface area if height and weight be known. Arch Int Med 1916; 17:863-71.