EndocrinologyADA Standards of Care 2026 · Section 2 · Interactive Decision Tool
Diabetes Diagnosis & Classification
ADA 2026 Standards of Care — Diagnosis criteria, prediabetes thresholds, screening recommendations, Type 1 vs Type 2 classification, and gestational diabetes · Diabetes Care 2026;49(Suppl 1):S27–S49
Step 1 — Select Clinical Scenario
What is the clinical question?
Select the pathway that best describes the current situation — each generates evidence-based guidance from ADA 2026 Section 2
🔬 Diagnose Diabetes
Patient has test results or symptoms — enter A1C, fasting glucose, 2-h OGTT glucose, or random glucose to determine diagnosis
📋 Screening Criteria
Asymptomatic patient — determine whether to screen for prediabetes and diabetes based on age, BMI, and risk factors
🔎 Classify Diabetes Type
Diabetes already diagnosed — use clinical features, AABBCC tool, and laboratory markers to distinguish Type 1 vs Type 2 vs other forms
🤰 Gestational Diabetes
Pregnant patient — screening timing, diagnostic criteria (one-step and two-step), and postpartum follow-up per ADA 2026
Step 2 — Enter Test Results (Table 2.1 + 2.2)
Enter available test values
Leave fields blank if not tested — the tool interprets any combination. In the absence of symptoms, confirmatory testing is required.
NGSP certified assay · No fasting required
Fasting ≥8 hours · No caloric intake
75-g glucose load · ≥150 g carbs/day × 3 days prior
Step 2 — Patient Profile for Screening (Table 2.5)
Who is this patient?
ADA 2026 screening criteria for prediabetes and type 2 diabetes in asymptomatic adults
Patient age
Age ≥35 years
Age <35 years
BMI
BMI ≥25 kg/m² (general) or ≥23 kg/m² (Asian)
BMI <25 kg/m²
Risk factors — check all that apply
Prior testing results (if any)
No prior testing
Prior A1C 5.7%+ / IFG / IGT
History of gestational diabetes
Prior normal results
Step 2 — AABBCC Classification Tool (Fig 2.1)
Clinical features at presentation
Select all features that apply — based on ADA 2026 AABBCC mnemonic and Type 1 diabetes flowchart (Figure 2.1)
Important: Classification may not be straightforward at presentation. Misdiagnosis occurs in up to 40% of adults with new-onset Type 1 diabetes (misdiagnosed as Type 2). Classification should be revisited if clinical trajectory is unexpected.
Islet autoantibody result (if tested)
Positive (GAD65, IA-2, ZnT8, or insulin)
Negative (all tested)
Not yet tested
C-peptide level (if tested, after ≥3 years of diabetes)
<200 pmol/L (<0.6 ng/mL) — very low
200–600 pmol/L (0.6–1.8 ng/mL) — intermediate
>600 pmol/L (>1.8 ng/mL) — preserved
Not tested
Step 2 — Gestational Diabetes Assessment
Stage of pregnancy or postpartum
ADA 2026 GDM screening timing and diagnostic criteria — one-step and two-step approaches
<15 weeks — Early pregnancy
Screen high-risk patients for pre-existing (undiagnosed) diabetes using standard diagnostic criteria at first prenatal visit
24–28 weeks — GDM screening
Screen all pregnant women without known diabetes for gestational diabetes. Select one-step or two-step approach.
Postpartum — Follow-up testing
Post-delivery diabetes screening for women with GDM diagnosis and ongoing surveillance schedule
Enter GDM test values
Input 75-g or 100-g OGTT results to assess against diagnostic criteria (one-step or two-step)