Type 1 Diabetes TrialNet
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Information for Study Participants

Pathway to Prevention Study

Status: Recruiting

Eligibility Criteria

To be screened, you must fulfill at least one of the two conditions below:

  • 1 to 45 years of age and have a brother, sister, child, or parent with type 1 diabetes
  • 1 to 20 years of age and have a cousin, aunt, uncle, niece, nephew, half sibling, or grandparent with type 1 diabetes

About this Study

The Natural History Study of the Development of Type 1 Diabetes will study people at increased risk for type 1 diabetes to learn more about how type 1 diabetes occurs.

TrialNet is screening close blood relatives of people with type 1 diabetes because relatives of people with type 1 diabetes have a 10 to 15 times greater risk for developing the disease than people with no family history.


The study is divided into two parts: Screening and Monitoring. During screening, you will be tested for diabetes-related autoantibodies in the blood. Autoantibodies are proteins that are made by the body’s immune system. If these proteins are present, it could mean that cells in the pancreas which produce insulin are damaged. Certain kinds of autoantibodies can be found in the blood years before type 1 diabetes occurs.

If the screening blood tests show that you have autoantibodies, we will ask you to participate in the monitoring part of the study.


We will ask you to provide information about yourself and your family history of diabetes. We will take up to 1 tablespoon of blood at each visit to test for diabetes related autoantibodies. A member of the TrialNet research team will contact you if you have one or more autoantibodies present in the blood (you are positive). You will then be asked to return for a repeat blood test to confirm the presence of autoantibodies.

If we do not find autoantibodies in your blood (you are negative), you will receive results by letter. Testing negative for autoantibodies does not mean you will never get diabetes, but the chances are much lower than if you tested positive. It is still possible that you could develop autoantibodies in the future. For this reason, we will offer to test you each year until you turn 18. We may ask some people who are negative for antibodies to be in the monitoring part of the study so that we can compare their results with people who are positive.


Annual Monitoring for those with Autoantibodies at Screening

Individuals with one autoantibody will have an Oral Glucose Tolerance Test (OGTT) and HbA1c at the first monitoring visit to determine their monitoring plan. If these results confirm you are at a lower 5-year risk for diabetes, you will have Annual Monitoring. 

Annual monitoring visits include testing for autoantibodies and HbA1c. If your HbA1c increases or you develop two or more autoantibodies you will be asked to come for Semi-Annual Monitoring so that you can be followed more closely for possible progression towards type 1 diabetes.

Semi-Annual Monitoring for those with Autoantibodies at Screening

Individuals in this group have a higher 5-year risk of diabetes. They will be asked to come in for Semi-Annual Monitoring. This includes individuals found to have two or more autoantibodies during Screening. It also includes individuals that have one autoantibody as well as other test results that indicate a higher 5-year risk for diabetes.

Semi-annual Monitoring visits include blood tests for autoantibodies, HbA1c, as well as an (OGTT).

These tests are described here:

  • Oral Glucose Tolerance Test (OGTT)
    After an overnight fast (not eating during the night), you will have an OGTT. This test is done to measure the level of glucose (sugar) in the blood after you drink a sweet liquid that contains glucose over a 5-minute period. We will measure your height and weight. To make taking the blood easier, we will place an intravenous needle and plastic tube (IV) in a vein in your arm. Blood samples will be drawn through the IV before you drink the liquid and then at several times after you have finished drinking it. The entire test will take about 21/2 hours.

  • Autoantibody Test
    This test looks to see if you have diabetes-related autoantibodies in your blood. Autoantibodies are proteins that are made by the body's immune system. They are a sign that the cells in the pancreas that produce insulin could be damaged. These proteins can be found in the blood years before a person develops type 1 diabetes.

  • HbA1c Test
    This blood test measures a person’s average blood glucose level for last 2-3 months before the test.


Before you have the autoantibody test, you must give permission to have the test performed by signing an Informed Consent form. Parents must give permission for children under 18 years of age to be tested. Please read the Informed Consent form carefully. A TrialNet health professional will talk to you about the test and the Informed Consent form. Please discuss any questions or concerns with this TrialNet staff person.

If you choose to participate in the second or third phases of the study, we will ask you to sign a separate Informed Consent form for each phase.

If you participate in phase 1, you do not have to participate in any other phase of the study. For more information on the 3 phases of this study, please refer to the revised study fact sheet

To see if you might be eligible for this study and for a referral to a TrialNet site:

If you call us, you will receive:

  • A phone evaluation to find out if you might be eligible for any current TrialNet studies
  • A referral to the closest clinical site in your area
  • An information packet for the type of research that is of interest to you

If you wish to be tested for diabetes risk, but do not live near a TrialNet site, we will refer you to a TrialNet staff person at a Clinical Center who will explain the screening process and provide you with a test kit to have your blood test drawn by your own doctor or local laboratory.

Information will be kept confidential.

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