*4.4. Measurement of 51CrEDTA Clearance*

mGFR 51CrEDTA was determined from a single 51CrEDTA injection (activity 3 MBq) and four blood samples taken 120, 180, 240, and 300 min after intravenous application of the marker according to British Nuclear Medicine Society guidelines, using the By weight method. Samples were measured using a gamma counter (Hidex, Turku, Finland); mGFR 51CrEDTA was calculated and then adjusted to the patient's body surface area (Haycock formula) and specified as mL/min/1.73 m2 [32].
