I thought I d always had normal GFR results on my yearly physical blood work, but it turns out it dropped to 57 two years ago and 51 last year. I went in for bloodwork early because the dr wanted to ck my D3 level while taking calcium , and my GFR came back 52. I m worried because my Mom had kidney failure in her 70 s after having kidney issues all her life. He s redoing the blood test for the GFR level next week.
Thank you for using Chat Doctor. Glomerular filtration rate as calculated on a standard laboratory panel now utilizes a formula known as M Chat Doctor.  Since the advent of this formula and its use as the primary method of calculation of GFR on standard laboratory panels, there has been a more precise determination of GFR without a 24-hour urine collection.  Despite its increased accuracy, there are a few caveats in its interpretation. For example extremes of body weight and age do not yield accurate results. Furthermore, there is a 10% decline in GFR per decade after the age of 30-40.  In order to determine if there is a clinically relevant reduction in renal function or kidney disease for that matter, an urinalysis, evaluation of urine protein, renal ultrasound and serial creatinine assessments would be required at minimum. Should you want to simply answer your question of whether your GFR has declined from normal, all that is required is a 24-hour urine collection for creatinine clearance? Take care and be well