Which of the following statements regarding A1c is accurate, in relation to persons with diabetes?
A. Regardless of age or other factors, an A1c greater than 7% represents a medically unacceptable risk
B. A1c was recently adopted by the ADA as a diagnostic tool for diabetes because there is almost no variation among race, gender, or age and it remains largely unaffected by other medical conditions
C. Screening for diabetes by using the A1c has been shown to identify more cases of previously undiagnosed by diabetes than either the fasting plasma glucose or the 2 hour glucose tolerance test
D. The ADA recommends that the A1c test should be performed at least twice annually, and more often in some cases