HbA1C Not Accurate in Diabetic Dialysis Patients
HbA1C is a test commonly used by people who have diabetes to determine their overall blood sugar control over the past several weeks. Recently, it was brought to the attention of researchers at Wake Forest University Baptist Medical Center that the test was not accurate in their diabetic dialysis population.
This is startling news as over 200,000 diabetic dialysis patients have been using this test to gage their overall blood sugar control and getting a comfort zone that didn’t exist. Investigators reported in Kidney International, a scientific journal for nephrologists, that the HbA1C test grossly underestimates true glucose control in hemodialysis patients making them believe that they are in the ideal blood sugar range when in reality they are running unacceptably high blood sugars. This has come as a surprise to the nephrology community as the HbA1C has been the ‘gold’ standard for blood sugar tests.
This study evaluated 307 renal patients with diabetes – 258 with end-stage renal disease on hemodialysis and 49 who did not have kidney failure. The researchers looked at the HbA1C and compared it to a newer test called the glycated albumin, or GA test. The GA test measures the amount of blood sugar that has reacted with albumin, a protein in the plasma. The GA test reflects blood sugar control over the past 3 or 4 weeks.
Researchers believe that the major reason for the problem with HbA1C is that this test depends on red blood cell survival and these cells don’t live as long in hemodialysis patients. In fact, because of this red cell apoptosis, or death, many hemodialysis patients become anemic and require a hormone called erythropoietin to stimulate red blood cell production.
This study supports that the GA test is a more accurate measure of long-term blood sugar control among diabetic patients receiving dialysis. The problem is the GA test is not currently available in the US. Researchers state in conclusion that physicians and patients should be aware of the HbA1C underestimation of their blood sugar control and that the test is affected by both erythropoietin administration and the hemoglobin concentration.
About the Author
Kathy Shattler received her Master of Science degree from Michigan State University in E. Lansing Michigan in Human Nutrition. Her twenty-two years of practice includes holding positions as a Lecturer, Chief Clinical Dietitian and Program Manager. Kathy is the Founder of Nutri-Care Consulting and is currently the Nutrition Director of www.CEU4U.COM, an online continuing education management company for Registered Dietitians and Dietetic Technicians.
