What do you measure, what is your cut off, and what is your preferred kidney function assessment tool for prospective kidney transplant donors?

We measure kidney function by combination of 24 hour urine collection for creatinine clearance as well as estimated GFR using cystatin C based equation. We used to do Iothalamate clearance on a regular basis but due to staffing issue we have been doing this in very selected patients. Cutoff in gener...