Diabetes and Kidney Disease
Jean Robey, MD, is a board-certified physician in the fields of Internal Medicine and Nephrology on staff at Banner Estrella Medical Center. Her office can be reached at (623) 974-1763.
Question: I have had diabetes for more than four years. Recently, my primary care physician referred me to a kidney specialist and said my kidneys were working at less than 60 percent. How does he know this just from my blood work?
Answer: More than eight million people are affected by chronic kidney disease in the United States. Blood work and a urine analysis are used to evaluate patients with serious medical conditions like diabetes.
The kidney is a blood “filter” that filters the blood. The filtration process removes waste, balances electrolytes and discards substances our bodies make and we consume. This is what urine is. Abnormal levels of markers in the blood or abnormal appearance of substances in the urine can help identify kidney disease. One such marker in the blood is Creatinine. The creatinine level is used to calculate the glomerular filtration rate or to estimate the kidney's ability to filter. These estimates reflect the combined function of both kidneys.
The Glomerular Filtration Rate can be calculated using many different formulas or by direct measurement of a 24-hour urine collection. The widely accepted formula takes into account a person's age, race, and sex. This complicated formula can give a rough estimate of kidney function and can be interpreted as a rough “percentage” of normal kidney function.
Kidney function can be then “staged.” Higher stages denote lower function. Increasing stages as defined by the National Kidney Foundation have increased associated co morbidities. Stage 1 denotes normal function but abnormal excretion of protein whereas Stage 5 denotes severely decreased function and patients may require transplantation or dialysis.
Patients with evidence of abnormal kidney function by elevated creatinine and abnormal calculated Glomerular Filtration Rate or abnormal protein excretion may need further tests including more extensive blood work, radiographic imaging or intervention or kidney biopsy to help identify the cause.
Free screening for kidney disease is often available. Check local listing for the National Kidney Foundation and the Arizona Kidney Foundation.