A1C test not accurate for diabetics on dialysis

NEW YORK (Reuters Health) - The A1C test, the usual way of measuring long-range diabetes control, is not reliable for people who are undergoing hemodialysis, a new study shows.

"These results suggest that the nearly 200,000 diabetic hemodialysis patients in the US who use this test may not be receiving optimal care for their blood sugar," Dr. Barry I. Freedman, from Wake Forest University School of Medicine in Winston-Salem, North Carolina, said in a statement.

The A1C test measures how much of the hemoglobin in a person's blood is "glycated" -- has glucose attached to it -- and it reflects the level of glucose circulating over the long term. Glycated hemoglobin is designated HbA1c, or just A1C.

However, a more accurate measure is thought to be the amount of glycated albumin in the bloodstream, because it does not rely on the survival of red blood cells, which is typically reduced in hemodialysis patients.

As reported in the journal Kidney International, Freedman's team compared A1C and glycated albumin testing on blood samples obtained from 307 diabetic patients, including 258 who were on hemodialysis.

The outcome "supports the glycated albumin test as a more accurate measure of long-term blood sugar control among diabetic patients who are on hemodialysis," Freedman said.

However, the glycated albumin test is not available in the U.S. yet.

SOURCE: Kidney International, February 20, 2008.