Skip to content
Blood Test Tracker

ZnT8 Antibody (Zinc Transporter 8)

A blood test for antibodies against zinc transporter 8 (ZnT8), a protein in insulin-making cells. A positive result is linked to type 1 diabetes.

AI-verified against cited sources. Awaiting expert reviewAlso called ZnT8A, ZnT8 Ab, Anti-ZnT8LOINC 76651-9

Check your result

Sex (optional)

Type your result to see where it falls.

Nothing you type here leaves your browser.

What it is

Insulin is made by beta cells in the pancreas. In type 1 diabetes, the immune system attacks these cells and makes antibodies against proteins inside them. Zinc transporter 8 (ZnT8) is one of those proteins, found in the beta cell's insulin-storing granules. This test measures ZnT8 antibodies in a blood sample. It is one of four islet antibody tests, along with insulin, GAD65 and IA-2 antibodies. It does not measure the amount of zinc in your body.

Why it matters

ZnT8 antibodies help show that diabetes, or a risk of diabetes, comes from an autoimmune process (type 1 diabetes). Clinicians use islet antibody tests to sort out the type of diabetes, especially when it starts in adulthood, and to test relatives of people with type 1 diabetes. One positive antibody says less than two or more together. Finding two or more islet antibodies in a person with normal blood sugar and no symptoms marks an early stage of type 1 diabetes, and a referral to a specialist center may be considered. A negative result does not rule out type 1 diabetes, since 5% to 10% of people with it have no antibodies.

If it’s high

A result at or above your lab's cutoff (usually 15 U/mL) means ZnT8 antibodies were found. In someone with diabetes, this supports an autoimmune cause, which means type 1 diabetes, including the slower adult form. In someone without diabetes, it is linked to a higher chance of developing type 1 diabetes, especially when other islet antibodies are also positive. One positive antibody alone carries less weight, so clinicians often add other antibody tests or repeat the test.

Common causes

  • A false-positive result, since a single antibody test is imperfect and a second antibody test is often used to confirm
  • Early autoimmune activity before any symptoms, which is why relatives of people with type 1 diabetes are sometimes tested
  • Type 1 diabetes, including the slower-starting adult form sometimes called latent autoimmune diabetes in adults (LADA)

What can help

  • Ask whether other islet antibodies (GAD65, IA-2, insulin) should be checked, since two or more together carry more weight
  • Ask whether a repeat test or a visit to a diabetes specialist makes sense
  • Ask whether blood sugar tests, such as fasting glucose or A1C, are needed
  • Learn the early signs of high blood sugar, such as strong thirst, passing urine more often, weight loss without trying and tiredness

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 0–15 U/mL. Source: Mayo Clinic Laboratories, Quest Diagnostics, ARUP Laboratories.

What can affect your result

  • Time since diagnosis: ZnT8 antibodies are found in more people soon after type 1 diabetes starts and in fewer as the years pass
  • Ancestry: ZnT8 antibodies were less common in people of Asian ancestry in one large study
  • Other islet antibodies: two or more matter more than one
  • Test kit: most US labs use an ELISA with a cutoff near 15 U/mL, and other kits can differ
  • Labcorp asks for serum or plasma to be separated from the cells within 45 minutes of the blood draw and sent frozen, and rejects EDTA plasma, hemolyzed or fatty (lipemic) samples.
  • Quest rejects samples with gross hemolysis, lipemia or icterus, and accepts serum only.
  • ZnT8 antibodies are found in more people soon after type 1 diabetes starts and in fewer people as the years pass, so timing affects the result (Wenzlau 2015).
  • Kits can differ in cutoff, so only compare results from the same lab and kit.

ZnT8 antibodies are most often positive soon after type 1 diabetes starts, and become less common over the following years.

When to talk to a clinician

Talk with a clinician soon about a positive result, especially if you have very strong thirst, pass urine much more than usual, lose weight without trying, or feel unusually tired. Get emergency care (call 911 or your local emergency number) if you have very high blood sugar with vomiting, fast or deep breathing, or confusion.

Questions you could ask

  • Why was ZnT8 chosen for me, and how does it fit with my other results?
  • Should other islet antibodies (GAD65, IA-2, insulin) be checked?
  • Should this result be repeated or confirmed?
  • Do I need blood sugar tests or a visit to a diabetes specialist?
  • What signs of high blood sugar should I watch for?

Questions people ask

Does a positive ZnT8 antibody mean I have type 1 diabetes?

Not by itself. The ADA notes that having two or more islet antibodies marks an early stage of type 1 diabetes, and a single imperfect antibody test can misclassify some people. Clinicians combine it with blood sugar results and other antibodies.

Is this a zinc level test?

No. It looks for antibodies against a protein called ZnT8 that helps move zinc inside insulin-making cells. It does not measure the zinc in your blood.

Can ZnT8 antibodies be negative if I have type 1 diabetes?

Yes. In one large study, ZnT8 antibodies were found in a little over half of people within 3 years of diagnosis, and the ADA notes that 5% to 10% of people with type 1 diabetes have no antibodies. Testing several antibodies finds more cases.

Show the science and sources

For clinicians and researchers

ZnT8 (encoded by SLC30A8) is a zinc transporter in the membrane of insulin secretory granules. ZnT8 autoantibodies (ZnT8A) are one of four islet autoantibodies used in practice, with insulin, GAD65 and IA-2 (ADA 2025). In 1,504 people with type 1 diabetes sampled within 3 years of diagnosis, ZnT8A were found in 862 (57.3%), with the highest frequencies and titers at the shortest disease duration and significantly lower prevalence in people of Asian ancestry (T1DGC Autoantibody Workshop, Wenzlau 2015). The ADA Standards of Care 2025 state that screening for presymptomatic type 1 diabetes may use autoantibodies to insulin, GAD, IA-2 or ZnT8 (recommendation 2.6) and should be offered to those with a family history or elevated genetic risk (2.7), that when multiple confirmed islet autoantibodies are found, testing for dysglycemia can help forecast near-term risk and referral to a specialized center may be warranted (2.8), and that standardized islet autoantibody testing is recommended to classify diabetes in adults with overlapping features (2.9). In the ADA adult flowchart GAD is the primary antibody, followed by IA-2 and/or ZnT8 if negative, and 5% to 10% of people with type 1 diabetes have no antibodies. Stage 1 is two or more islet autoantibodies with normal glucose (about 44% five-year risk of symptomatic type 1 diabetes), and stage 2 adds dysglycemia (about 60% risk by 2 years and 75% by 5 years). The ADA also cautions that a single imperfect antibody test may misclassify some people with type 2 diabetes. ARUP advises that ZnT8 is most useful to establish an autoimmune cause in previously diagnosed type 1 diabetes, is not for telling type 1 from type 2 in most cases, and that at least two antibody tests should be done. Assays: ELISA at Quest, Labcorp and ARUP, all reporting U/mL (ARUP: Kronus Units, which it equates with U/mL), with a cutoff of 15 at Quest, ARUP and the Mayo send-out listing.

LOINC 76651-9 (primary). Specimen: serum.

Sources

  1. ZnT8 Antibodies (test FZNT8), Mayo Clinic Laboratories
  2. Zinc Transporter 8 (ZnT8) Antibody (test 93022), Quest Diagnostics
  3. Zinc Transporter 8 Antibody (test 2006196), ARUP Laboratories
  4. ZnT8 Antibodies (test 503995), Labcorp
  5. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2025, Diabetes Care (American Diabetes Association) (2025)
  6. Staging presymptomatic type 1 diabetes: a scientific statement of JDRF, the Endocrine Society, and the American Diabetes Association, Diabetes Care (2015)
  7. Changes in Zinc Transporter 8 Autoantibodies Following Type 1 Diabetes Onset: The Type 1 Diabetes Genetics Consortium Autoantibody Workshop, Diabetes Care (2015)
  8. Type 1 Diabetes, MedlinePlus (U.S. National Library of Medicine)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

Related markers