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Test Code IA2* Islet Antigen 2 (IA-2) Antibody, Serum

Reporting Name

IA-2 Ab, S

Useful For

Clinical distinction of type 1 from type 2 diabetes mellitus


Identification of individuals at risk of type 1 diabetes (including high-risk relatives of patients with diabetes)


Prediction of future need for insulin treatment in adult-onset diabetic patients

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Ordering Guidance

Islet cell antigen 2 (IA2) testing is available individually (this test) and with glutamic acid decarboxylase 65-kilodalton isoform (GAD65), insulin, and zinc transporter 8 (ZnT8) antibodies as a part of DBS1 / Diabetes Mellitus Type 1 Evaluation, Serum. The evaluation is most appropriate to order in the following clinical contexts: -Distinguishing type 1 (autoimmune) diabetes mellitus from type 2 diabetes mellitus -Identifying individuals at risk of type 1 diabetes (including high-risk relatives of patients with diabetes)  -Predicting future insulin requirement treatment in patients with adult-onset diabetes   Individual antibody testing would be more appropriate if 1, 2, or 3 of the analytes (GAD65, IA-2, insulin, ZnT8 antibodies) have already been tested and reported negative, and the provider wishes to test for the balance of remaining untested analytes only.

Specimen Required


Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 1.5 mL

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  72 hours

Reference Values

≤0.02 nmol/L

Reference values apply to all ages.

Day(s) Performed

Monday through Friday

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
IA2 IA-2 Ab, S 81155-4


Result ID Test Result Name Result LOINC Value
89588 IA-2 Ab, S 81155-4

Report Available

3 to 9 days

Method Name

Radioimmunoassay (RIA)