GFR less than 60 indicative of kidney disease?

1 I have taken care of a few patients with GFR less than 60 but other labs values were within normal limits.Creatine ok,no protein in urine.I was wondering if GFR alone can be indicative of kidney disease,and how come the doctors just basically disregarded those values as everything was normal...
A GFR below 60 indicates some kidney damage has occurred.

But there are other lab marks too:potassiumurine proteinanemia markerspth24 hr urineus others depending on the disease process

Quote from traumaRUsBut there are other lab marks too:potassiumurine proteinanemia markerspth24 hr urineus others depending on the disease process

GFR less than 60 is stage 3 kidney disease, at this point the pt shod be referred to Nephrology. When I worked disease Mgmt Nephrologists stressed how they want to see these pts at the earliest stage possible to start treatment in order to delay progression of the disease. Less than 30 is stage 4 and at this point a fistula is initiated because once the pt reaches stage 5 it's ESRD and pt starts dialysis.