Scope of this summary
Keep issuer recommendations separate
USPSTF: screen adults aged 35 to 70 years who have overweight or obesity, and offer or refer adults with prediabetes to effective preventive interventions. Consider earlier screening for populations with disproportionately high prevalence and for named individual risk factors. For Asian American adults, consider a lower BMI cut-point; the USPSTF notes that BMI ≥23 kg/m² may be appropriate.
ADA 2026: assess risk in asymptomatic adults; test at any age when overweight or obesity is accompanied by at least one risk factor, and otherwise begin by age 35. If results are normal, repeat at least every 3 years, with earlier testing when risk warrants it.
Tests used for screening or diagnosis
- A1C (HbA1c).
- Fasting plasma glucose.
- Two-hour plasma glucose during a 75-g oral glucose tolerance test.
- Interpret each test in the context of conditions that alter red-cell turnover, hemoglobin, glucose handling or assay reliability.
ADA diagnostic thresholds for diabetes
- A1C: ≥6.5% (≥48 mmol/mol).
- Fasting plasma glucose: ≥126 mg/dL (≥7.0 mmol/L).
- Two-hour plasma glucose after a 75-g load: ≥200 mg/dL (≥11.1 mmol/L).
In the absence of unequivocal hyperglycemia, confirm an abnormal diagnostic result using the approach specified by the ADA source.
ADA laboratory ranges for prediabetes
- A1C: 5.7–6.4% (39–47 mmol/mol).
- Fasting plasma glucose: 100–125 mg/dL (5.6–6.9 mmol/L).
- Two-hour plasma glucose: 140–199 mg/dL (7.8–11.0 mmol/L).
These ranges identify increased diabetes risk; they are not a pass/fail statement about one person's future health.
Safety and escalation boundaries
- Polyuria, polydipsia, weight loss, ketones, vomiting, dehydration, altered mental status or marked hyperglycemia requires a symptomatic or emergency diabetes assessment rather than this screening pathway.
- Do not use A1C alone when red-cell turnover, hemoglobin variants, pregnancy, recent blood loss or transfusion, kidney disease or another condition makes it unreliable.
- A result near a diagnostic boundary should be confirmed using the ADA approach unless unequivocal hyperglycemia is present.
- Suspected type 1 diabetes, gestational diabetes or a hyperglycemic crisis follows a separate time-critical pathway.
Applying the sources at the point of care
Source documents
Use the linked source documents for complete recommendations, evidence grading, exclusions and implementation detail.
- U.S. Preventive Services Task ForcePrediabetes and Type 2 Diabetes: ScreeningFinal Recommendation Statement · Grade B · published 2021-08-24 · accessed 2026-08-20view source
- American Diabetes Association Professional Practice Committee for Diabetes2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes—2026DOI 10.2337/dc26-S002 · published 2025-12-08 · accessed 2026-08-20view source
From guidance to deliberate practice and evidence
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