( CNN ) -- A diabetes test that measures a person 's average blood glucose control over the preceding two to three months is being recommended as the new diagnostic tool for the condition . Diabetics have too much glucose in their blood when the condition is uncontrolled , and must monitor it . A committee of international experts recommended the test , called the the A1C assay , at the American Diabetes Association 's 69th Scientific Sessions over the weekend . The report could instigate a change in the way diabetes is diagnosed , the American Diabetes Association said . The A1C assay , which has been used for nearly 30 years to determine how well a patient controls diabetes , is a more stable , reliable diagnostic tool than the techniques currently in use , the authors of the report said . `` This committee that I chaired is recommending that this be used as widely as possible to diagnose diabetes instead of the blood sugar test , '' said Dr. David Nathan , director of the Diabetes Center at Massachusetts General Hospital and chairman of the committee . The A1C test , which consists of a simple blood test , is also more convenient than the two tests commonly used for diabetes -- the fasting plasma glucose and the oral glucose tolerance test -- the authors said . In the fasting test , the patient does not eat for about 12 to 14 hours before a blood test . In the tolerance test , the patient drinks a sweet solution and has blood drawn two hours later . In addition , Nathan said , `` It probably is better related to the development of eye disease with diabetes , and therefore probably serves as a better diagnostic tool . '' The international committee was assembled by the American Diabetes Association , International Diabetes Federation and European Association for the Study of Diabetes , but those organizations have not officially endorsed the report . `` Basically , the American Diabetes Association supports the concept , supports the use of the A1C to diagnose diabetes , and just has to look at the implications of it , and the implementation of it , '' said Richard Kahn , Chief Scientific and Medical Officer for the American Diabetes Association , who was part of the committee . Using A1C in diagnosis would be particularly useful for determining whether patients have type 2 diabetes , which is more difficult to diagnose than type 1 , said Dr. William Bornstein , assistant professor of endocrinology at Emory University , who was not part of the committee . `` This will be beneficial to the population in terms of helping us more clearly diagnose folks who are at risks for complications and help them manage that earlier , '' Bornstein said . Still , controversy likely will arise over the use of the A1C in diagnostics because of the long , established track record of using the other two methods , Bornstein said . iReport.com : Boxing champ talks about diabetes struggle . How it works . Humans can not live without having sugar called glucose in their blood . Too much glucose , however , attaches to a variety of proteins in the body and harms them . Uncontrolled diabetes is characterized by too much glucose in the bloodstream . This excess glucose then glycates with -- or sticks to -- a protein called hemoglobin , which carries oxygen from the lungs to the body 's cells . The A1C test measures the percentage of glycated hemoglobin in the blood , which is a reflection of average blood glucose control , according to the American Diabetes Association . A1C is a better measure of the problem that diabetes causes than glucose-based tests , at least for monitoring , said David Schoenfeld , professor of biostatistics at Harvard University . He and colleagues , including Nathan and a large group of international researchers , studied the relationship between A1C and average blood glucose . While many diabetics monitor their average blood glucose levels daily , at the doctor 's office the patient receives a measurement in terms of hemoglobin A1C , Schoenfeld said . He and researchers created a chart to convert these two measurements , so that patients would not have to interpret two different numbers and feel confused . They concluded in a 2008 paper that , for most patients with type 1 and type 2 diabetes , A1C levels can be expressed as average glucose . The international committee concluded that an A1C level of 6.5 percent indicates that a person has diabetes , while values between 6 percent and 6.5 percent are likely to be at highest risk for developing diabetes . Experts note , however , that there is a continuum of risk for complications , and the `` cut-point '' of 6.5 percent should not be considered an absolute dividing line . All adults who are overweight and have additional risk factors , such as family history of diabetes , high blood pressure or abnormal lipid levels , should be screened for diabetes , according to the American Diabetes Association . Adults aged 45 or older should be tested even if they do not have these risk factors , the association said .
Committee says A1C test is more reliable and convenient than other tests . Tests in use now are fasting plasma glucose and oral glucose tolerance test . Comment: Expert : Report may cause controversy because of track record of using current tests .