🧬 T1D: 90%–95% have ≥1 islet autoantibody at dx

A JAMA review reports 90%–95% of people with type 1 diabetes (T1D) have ≥1 islet autoantibody at diagnosis—helping distinguish T1D from type 2 or monogenic diabetes and supporting earlier identification of autoimmune disease.

Why It Matters To Your Practice

• T1D is autoimmune beta-cell destruction causing insulin deficiency and accounts for ~5%–10% of diabetes cases.

• Islet autoantibodies (insulin, GAD65, IA-2, ZnT8) are typically absent in type 2 and monogenic diabetes—useful when the phenotype is unclear (eg, adult-onset, overlapping features).

• Autoantibodies can be present before symptoms, aligning with the concept of earlier-stage T1D and prompting closer monitoring when identified.

Clinical Benefits

• Supports correct classification at diagnosis, which helps guide immediate insulin initiation and avoids delays that raise DKA risk.

• Informs patient counseling: T1D requires lifelong insulin replacement (injections or pump) and ongoing glucose monitoring.

• Reinforces technology benefits: CGM + insulin pump systems that auto-adjust delivery can reduce hypoglycemia and improve A1c, especially when baseline A1c is >8%.

Managing Risks

• DKA remains common at presentation: up to 44% of children and 23% of adults present in DKA—maintain a low threshold to assess ketones and acid-base status in symptomatic hyperglycemia.

• Don’t assume “adult = type 2”: median age of T1D diagnosis in the US is 24 years, and adult onset is common.

• Plan for complications: T1D is linked to microvascular and macrovascular disease, including cardiovascular disease—build in early risk-factor management and screening.

The Bottom Line

• In suspected T1D, islet autoantibodies are present in 90%–95% at diagnosis and can help differentiate from type 2 and monogenic diabetes.

• Early recognition plus timely insulin and CGM/pump support can reduce acute risk (DKA, hypoglycemia) and improve glycemic outcomes.