Factors that can affect the eGFR:
(1) use in a population other than the one used to develop the equation (normal renal function vs chronic kidney disease, race, age)
(2) pregnant female
(3) neonates, infants and toddlers
(4) advanced age
(5) glomerular hyperfiltration (diabetics, others)
(6) acute renal failure
(7) rapidly changing renal function (unstable renal function)
(8) certain diets (vegetarian, low-meat diet)
(9) creatine dietary supplements
(10) unusual or unpredictable changes in muscle mass (myopathy, neuromuscular disease)
(11) high muscle mass (body builders)
(12) low muscle mass (frail elderly, critically-ill, cancer patients)
(13) severe malnutrition
(14) body mass index less than 20 kg per square meter
(15) morbid obesity
(16) renal transplant
(17) critically ill
(18) multiple comorbid conditions
(19) medications
(20) use of creatinine alone as the filtration marker