What does it mean to have kidney function a little high?

What does slightly decrased kidney function mean? and can diet fix it?

• Answer:

  The term is rather vague and if may not have any real meaning. Physicians include a serum creatinine when they perform laboratory chemistries. The creatinine is an indirect measure of kidney function. Although the normal range is most often up to 1.2 to 1.3 mg/dL or 106 to 115 mmol/L it typically does not exceed 1.0 mg/dL or 88.4 mmol/L. Beginning around age 30 renal function decreases about 1% percent per year meaning that an 80 year old with a normal creatinine has lost about 50% of renal function. This is part of the reason that I suggest that the creatinine is an indirect measure of renal function. The creatinine clearance is a specific measurement of renal function. Urine is collected for 24 hours and when it is dropped off blood is drawn for a serum creatinine. The laboratory then determines the creatinine clearance which is slightly lower in women than in men. In either gender however normal would be in excess of 100 ml/min or 1.67 ml/sec. For about the past 5 years laboratories have been including an estimated glomerular filtration rate. This is a very pernicious habit as the formula to calculate eGFR is notoriously unreliable and underestimates renal function. Thus it is very common for a person with normal renal function to have a supposedly low eGFR. This in turn results in many people being labeled as having decreased renal function when they do not. If I may be of further assistance please let me know. I wish you the very of health and in all things may God bless.