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

Important Note

Effective 1/12/18

EXPLANATION: To decrease the frequency of test cancellations due to insufficient volume the minimum volume for IA2: Islet Antigen 2 (IA-2) Antibody, Serum is increasing. The new minimum volume is 1.0 mL.

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

Serum


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


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


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. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86341

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

Interpretation

Seropositivity for islet antigen 2 autoantibody (> 0.02 nmol/L) is supportive of:

-A diagnosis of type 1 diabetes

-A high risk for future development of diabetes

-A current or future need for insulin therapy in patients with diabetes

Clinical Reference

1. Shields BM, Shepherd M, Hudson M, et al. Population-based assessment of a biomarker-based screening pathway to aid diagnosis of monogenic diabetes in young-onset patients. Diabetes Care. 2017;40(8):1017-1025. doi:10.2337/dc17-0224

2. Bingley PJ. Clinical applications of diabetes antibody testing. J Clin Endocrinol Metab. 2010;95(1):25-33

3. Bingley PJ, Bonifacio E, Mueller PW. Diabetes Antibody Standardization Program: first assay proficiency evaluation. Diabetes 2003;52(5):1128-1136 

4. Christie MR, Roll U, Payton MA, et al. Validity of screening for individuals at risk for type I diabetes by combined analysis of antibodies to recombinant proteins. Diabetes Care. 1997;20(6):965-970

5. Lampasona V, Petrone A, Tiberti C, et al: Zinc transporter 8 antibodies complement GAD and IA-2 antibodies in the identification and characterization of adult-onset autoimmune diabetes: Non insulin requiring autoimmune diabetes (NIRAD) 4. Diabetes Care. 2010;33(1):104-108

Report Available

3 to 9 days

Method Name

Radioimmunoassay (RIA)