Type 2 diabetes: screening & A1c target
Recommendations
USPSTF2021Grade B
Screen adults 35-70 with overweight or obesity for prediabetes and type 2 diabetes (fasting glucose, A1c, or OGTT), and offer or refer those with prediabetes to effective preventive interventions. Consider screening earlier in groups with higher diabetes prevalence, and at BMI ≥23 in Asian Americans. If normal, rescreening every 3 years may be reasonable.
Verify at USPSTF (opens in a new tab)ADA2026
Screen all adults ≥35 (earlier with risk). A1c goal <7% for most nonpregnant adults; individualize (e.g., <8% if limited life expectancy/comorbidity).
Verify at ADA (opens in a new tab)ADA2026Grade A / B / E
Individualize goals. A1C <7% suits many nonpregnant adults without significant hypoglycemia (A); <6.5% may suit those in good health with low treatment risk and burden (B); less stringent goals, eg up to 8%, for frailty, cognitive or functional limits, severe comorbidity, or limited life expectancy (B). With CGM, aim for time in range >70%. Check A1C at least twice yearly, about every 3 months if not at goal or after therapy changes (E).
Verify at ADA (opens in a new tab)ADA2026Grade A / E
Prediabetes: test for diabetes at least yearly (E). Refer adults with overweight or obesity at high risk to a diabetes prevention program aiming for at least 5-7% weight loss and ≥150 minutes a week of moderate activity (A). Consider metformin for high-risk adults, especially ages 25-59 with BMI ≥35, fasting glucose ≥110 mg/dL, and A1C ≥6.0%, and those with prior gestational diabetes (A). Do not avoid or stop statins because of diabetes risk; monitor glucose instead (B).
Verify at ADA (opens in a new tab)Who this applies to
- USPSTF 2021 (Grade B): adults 35 to 70 with overweight or obesity (BMI 25 or higher; 23 or higher is a reasonable cutoff for Asian Americans). Repeat about every 3 years if normal.
- ADA Standards of Care 2026: test all adults from age 35. Test at any age with overweight or obesity plus a risk factor: first-degree relative with diabetes, high-risk ancestry, cardiovascular disease, hypertension, HDL under 35 or triglycerides over 250, polycystic ovary syndrome, physical inactivity, or insulin-resistance conditions such as acanthosis nigricans or fatty liver disease. HIV, high-risk medicines and past pancreatitis call for close monitoring.
- Women with a history of gestational diabetes: lifelong testing every 1 to 3 years. Anyone with prediabetes: test yearly.
How it is done in practice
- Fasting glucose, A1c, or a 2-hour 75 g glucose tolerance test. Diabetes: A1c 6.5 percent or more, fasting 126 or more, 2-hour 200 or more, or a random 200 or more with symptoms. Prediabetes: A1c 5.7 to 6.4, fasting 100 to 125, 2-hour 140 to 199. Confirm with a second test unless symptoms are unequivocal.
- A1c misleads with hemoglobin variants, hemolysis, recent transfusion, iron deficiency, advanced kidney disease and pregnancy. Use glucose criteria in those situations.
- Targets: A1c under 7 percent for most nonpregnant adults. Less stringent, such as under 8 percent, when life expectancy is limited, hypoglycemia has been a problem, complications are advanced, or the burden of treatment outweighs the benefit. Tighter, around 6.5 percent, only when reached without hypoglycemia.
- With continuous glucose monitoring, time in range 70 to 180 mg/dL above 70 percent with under 4 percent below 70 is the working equivalent of an A1c under 7.
What changed recently
USPSTF 2021 lowered the starting age from 40 to 35 and framed prediabetes as a target for prevention, not just a label. The ADA keeps universal testing from 35 and, in its 2026 standards, chooses first drugs by comorbidity rather than by A1c alone (see the drug selection page).
Points that matter in clinic
- Prediabetes: refer to a CDC-recognized Diabetes Prevention Program, which cut progression by 58 percent in the DPP trial and by 71 percent in people over 60. Consider metformin for high-risk prediabetes, especially at ages 25 to 59 with BMI 35 or more, fasting glucose 110 or more and A1c 6.0 percent or more, and after gestational diabetes (ADA 2026).
- At diagnosis: dilated eye exam, urine albumin-to-creatinine ratio, eGFR, lipids, foot exam, and blood pressure. Check B12 periodically once on metformin.
- A1c reflects roughly 3 months of glucose. Rechecking sooner than 3 months after a change measures the old regimen.