Please explain what a high level of gfr is in a blood test. ?

Kidney level: Gfr stands for glomerular filtration rate. It is an estimate of the total kidney function. Hi GFR is normally not a problem. It can occur normally in young patients, and may be elevated in early stages of diabetic nephropathy.

Ignore it: The "gfr" given on lab sheets these days is a subscientific estimate of the rate at which water passes from blood into the the filtrate that will become urine. For a healthy person, the "gfr estimate" is not helpful. It ignores variability in body musculature, how much protein you have eaten recently, and other factors.