A "normal" Glomerular Filtration Rate (GFR) within the context of kidney disease depends on the stage of the kidney disease. Specifically, in Stage 1 CKD, a normal GFR is generally considered to be 90 or greater, even though kidney damage (like protein in the urine) may be present. This indicates that the kidneys are still functioning well at this stage, despite the presence of some indicators of kidney damage.
In other words, it's more accurate to say a GFR of 90 or above indicates normal kidney function, which can occur even with early kidney disease.
