8 Things to Know About Autoantibody Testing for T1D

This blood test checks for certain antibodies that attack healthy cells (a.k.a. autoantibodies), indicating you could develop type 1 diabetes. (It is also used to confirm a T1D diagnosis.) You shouldn’t need to fast before it, although your doctor may also order a C-peptide test, which you do need to fast for, to measure your baseline pancreas function, says Emily Nosova, M.D., an endocrinologist at Mount Sinai Health System in New York City. It may take a few weeks for your results to come back, Dr. Nosova notes; the test can be performed on kids, teens, and adults.

These tests specifically look for five different antibodies, says Dr. Nosova: the GAD65, the zinc transporter 8 antibody, the islet cell antibody, the IA-2 antibody, and the insulin antibody. These antibodies are created by your body to help fight off invaders (like germs and viruses), but they can end up targeting your pancreas and its beta cells that produce insulin, the hormone that regulates your blood sugar level. You might be born with the antibodies, or they can develop over time, possibly being triggered by a virus or other illness, Dr. Nosova explains.

A positive test will show the presence of two or more of these type-1-indicating antibodies, says certified diabetes educator Gary Scheiner, the owner of Integrated Diabetes Services in Wynnewood, PA, and the author of Think Like A Pancreas. “Someone who has one antibody—they’ve got about a 15% chance of developing type 1 diabetes in the next five years,” he says. “If they have two or more, the [five-year] risk goes up to almost 45%, and the risk of them developing type 1 in the next 15 to 20 years starts approaching 100% at that point.”

These autoantibody tests are not ones that your doctor will perform automatically—you have to ask for them specifically, or your doctor may suggest it if your parent or sibling has type 1 since you are more at risk, Scheiner says. “In the general population, about one in 300 people develop type 1 diabetes, but if you’re a first-degree relative of someone with type 1, that risk is one out of 20,” he points out. The tests are also used if you are newly diagnosed with diabetes as an adult and doctors aren’t sure whether you have type 1 or type 2.

Talk to your doctor about whether this autoantibody test is right for you and be sure to mention any direct family history of type 1 diabetes when you do. You can ask for a prescription and have this test performed at any general lab, says Scheiner, an award-winning diabetes educator who has been living with type 1 diabetes for nearly 40 years. In terms of finding a place to do the test, TrialNet-affiliated clinics are a popular choice nationwide; TrialNet is a research network that works to explore “ways to prevent, delay, and reverse the progression of type 1 diabetes.”

Depending on your level of antibodies, you may be able to take a medication that has shown to delay the onset of type 1 diabetes progression and postpone the need for insulin therapy, says Silvana Obici, M.D., the chief of the division of endocrinology and metabolism in the department of medicine at the Renaissance School of Medicine at Stony Brook University in Long Island, NY. This FDA-approved therapy is called Tzield (teplizumab-mzwv). Plus, if you know ahead of time, your physician can keep tabs on your blood sugar level and pancreatic function for years, Dr. Nosova says.

If your test comes back positive, “you may have some degree of anxiety knowing that you may not have a functional pancreas over time,” Dr. Nosova says. “But know that process is extremely variable from person to person.” You could stay in the “honeymoon period” (where your body is still producing some insulin) for months to years. And, the fact is, “knowledge is power now,” Scheiner says. Again, knowing sooner could make a difference in your long-term health by delaying the need for insulin, or could mean you’re being closely monitored so you don’t develop complications like diabetic ketoacidosis.

Considering some of the pros, you may wonder why this testing isn’t performed on everyone. Dr. Nosova says this is because T1D is less common than other autoimmune diseases, so testing “hasn’t been shown to be cost-effective, or really beneficial on a public health level… at least not yet.” However, Dr. Obici says that there’s international debate over whether testing everyone could be beneficial. For instance, Italy successfully passed a law introducing nationwide screening for type 1 for the general population last year, with the aim of “reducing the effects of chronic disease,” per the Lancet Diabetes & Endocrinology.

All told, Scheiner says that this autoantibody test is worth having, particularly if you have a direct family member who already has type 1 diabetes. Knowing what lies ahead if you test positive can help you and your doctor make a game plan and work to improve your long-term outcome. Although it can be scary to take a test like this and get a positive result, Scheiner says it’s best not to “bury your head in the sand.” As he puts it: “If we know ahead of time, we can be strategic and delay and minimize how severe the damage becomes.”