How Lab Tests Separate the Types

Autoantibodies are immune system proteins. Think of them as a guard that mistakes your own cells for intruders. In type 1, they often target the beta cells that make insulin. A blood test can look for them.

They are often found in type 1 and in LADA. LADA is a form of diabetes that often starts in adults. They are typically not found in type 2.

Your pancreas is the organ that makes insulin. Each time it makes insulin, it also releases C-peptide. Think of C-peptide as a receipt for insulin. A blood test measures it, showing how much insulin your body still makes.

Low C-peptide points toward type 1. Normal or high C-peptide points toward type 2.

Very high blood sugar can lower C-peptide for a while. Doctors keep that in mind.

Doctors look at your health history. They ask when symptoms began and how old you were. They also ask about weight changes. Age and weight are clues, like puzzle pieces, not final answers.

Type 2 can happen at a normal weight. Symptoms alone cannot name the type. Only a clinician, like your doctor, makes the diagnosis. A positive result needs a repeat on another day to confirm it.

Key takeaways

• Autoantibodies are often found in type 1 and LADA, and typically not in type 2.
• Low C-peptide points toward type 1, while normal or high C-peptide points toward type 2.
• Only a clinician makes the diagnosis, using history, lab tests and repeat checks.

Try it

Before your next visit, write down when your symptoms began and how your weight has changed. Then ask your care team which tests they plan to order.