Guideline on the use of iodinated contrast media in patients with kidney disease 2018

How to Estimate GFR Using Serum Cystatin C eGFRcys (mL/min/1.73m 2 )In males: (104 × S cys -1.019 × 0.996 age [years] ) 8In females: (104 × S cys -1.019 × 0.996 age [years] 0.929) 8Serum cystatin C (S cys ) levels are expressed in milligrams per liter (mg/L) based on the international reference material for cystatin C (ERM-DA471/IFCC).# As S cys levels are less affected by muscle mass, diet, and physical activity, they are considered useful when an estimation of GFR by SCr levels is difficult, as in the following cases: Patients with low muscle mass (e.g., quadruple amputee, prolonged bed rest, emaciation) Patients with large muscle mass (e.g., athletes, elderly who exercise regularly) # Other factors that reportedly affect S cys levels are pregnancy, HIV infection, and thyroidal dysfunction.The influence of certain conditions and drugs is not sufficiently understood.