A panel of international experts is recommending that the way diabetes is diagnosed be dramatically simplified, a move likely to be embraced by doctors and patients alike.
The committee says that A1C, a blood test that measures the amount of sugar that latches onto red blood cells over a period of months, can accurately determine who has diabetes.
Until now, most physicians used two more ponderous diagnostic tests: The fasting plasma glucose test requires patients to fast overnight, and the oral glucose tolerance test requires patients to drink an ultra-sweet liquid then hang around a couple of hours for a blood test. The tests also have to be done a second time to confirm a diabetes diagnosis.
“Testing for diabetes using A1C is more convenient and easier for patients who will no longer be required to perform a fasting or oral glucose tolerance test,” said Dr. David Nathan, director of the Diabetes Center at Massachusetts General Hospital in Boston and chair of the expert group.
The committee said that anyone with an A1C value of 6.5 per cent or greater should be considered diabetic.
Dr. Stewart Harris, chair of diabetes management at the University of Western Ontario in London, Ont., said the new approach will improve screening for diabetes.
“This will be a one-stop – simple and easy,” he said.
It will also be more expensive. The fasting plasma glucose test costs less than $1, while the A1C test costs $6-8.
“There will be an economic implication to this decision,” Dr. Stewart said.
Read the experts' recommendation
About two million Canadians suffer from diabetes, according to the Canadian Diabetes Association. There are three distinct forms of diabetes: gestational diabetes is a temporary condition that occurs during pregnancy; type 1 diabetes, usually diagnosed in children, occurs when the pancreas is unable to produce insulin; type 2 diabetes, which accounts for 90 per cent of cases, occurs when the pancreas does not produce enough insulin or the body does not effectively use the insulin it produces.
It is recommended that everyone over the age of 40 be screened for type 2 diabetes, and that testing be redone every three years. People should be tested at a younger age if they have high blood pressure, high cholesterol, or if they are overweight.
Dr. Amir Hanna, a staff endocrinologist at St. Michael's Hospital in Toronto, said the A1C test is currently used to monitor patients with diabetes and he is would be pleased to see it used as a screening test.
“This is great - a welcome addition to diabetes care,” he said.
Dr. Hanna said the reason A1C has not been used to screen for diabetes until now is largely technical: Only recently did all labs start using a standard assay so tests results are consistent and comparable.
A1C refers to a change in normal hemoglobin through a process called glycation – the ability to incorporate glucose into the hemoglobin molecule. As each red cell lives 120 days so the A1C tests provides accurate information on the average level of glucose (blood sugar) in the last 2-3 months.
When a person is sedentary, overweight and has high blood pressure or high cholesterol, all the vital organs are stressed. This causes the body to make too little insulin and to respond poorly to the little it does make, triggering diabetes.
Fluctuating insulin levels, in turn, cause serious damage to blood vessels. As a result, diabetes is the leading cause of blindness, amputation and kidney failure, and is one of the leading causes of cardiovascular disease. To prevent diabetes or control it, blood-sugar levels need to be kept in check.
