Anti-tyrosine phosphatase-like insulinoma antigen 2 (IA-2/IA2) antibodies

Blood Sciences Test

SPECIMEN TYPES:

Serum samples for GAD, IA-2 and ZnT8 testing only (minimum 500 µL serum): Please send with your local Pathology request form to Blood Sciences Laboratory.

TRANSPORT OF SPECIMEN:

First class post at room temperature

NORMAL RANGE:

IA-2 Positive: >/= 7.5 U/mL

TARGET REPORTING TIME:

2 weeks

** Please note (March 2024) – We are currently experiencing delays in analysis due to reagent shortages. The current expected TAT is 4-6 weeks. **

COST:

£29.04 (all three antibodies)

Test Usage

Autoantibodies recognising the islet cell antigens glutamic acid decarboxylase (GAD 65), Zinc Transporter 8 (ZnT8) and the anti-tyrosine phosphatase-like insulinoma antigen 2 (IA-2) are present in up to 90% of newly diagnosed patients with type 1 diabetes. The prevalence of GAD, IA-2 and ZnT8 autoantibodies is less than 1% in GCK, HNF1A and HNF4A MODY, and testing for these autoantibodies close to diagnosis gives very good discrimination of Type 1 diabetes from MODY (McDonald et al 2011 Diabet Med 28:1028-1033). The Blood Sciences department at the Royal Devon & Exeter Hospital offers a highly sensitive, automated ELISA method for the quantitative determination of GAD, IA-2 and ZnT8 autoantibodies in serum samples.

Turnaround time

10 working days

Availability

In House

REFERRALS

We welcome referrals for IA-2. If you are a new requestor please complete the following form: New requestor form

We now also have the option to use NPEx for referral requesting.

Further information about sample requirements for this test can be found here: GAD IA2 ZnT8 – further information

Specimen Labelling Procedure

Assayed By

This investigation is performed at the Royal Devon & Exeter Hospital (Wonford)
References

Brooking H, Ananieva-Jordanova R, Arnold C, Amoroso M, Powell M, Betterle C, Zanchetta R, Furmaniak J, Smith BR. A sensitive non-isotopic assay for GAD65 autoantibodies. Clin Chim Acta. 2003 May; 331(1-2):55-9.
Nilson E, Ekholm B, Rees Smith B, Törn C, Hillman M. Calcium addition to EDTA plasma eliminates falsely positive results in the RSR GADAb ELISA. Clin Chim Acta. 2008 Feb; 388(1-2):130-4.
A comparison of serum and EDTA plasma in the measurement of glutamic acid decarboxylase autoantibodies (GADA) and autoantibodies to islet antigen-2 (IA-2A) using the RSR radioimmunoassay (RIA) and enzyme linked immunosorbent assay (ELISA) kits. Rahmati K, Lernmark A, Becker C, Foltyn-Zadura A, Larsson K, Ivarsson SA, Törn C. Clin Lab. 2008; 54(7-8):227-35.
McDonald TJ, Colclough K, Brown R, Shields B, Shepherd M, Bingley P, Williams A, Hattersley AT, Ellard S. 2011. Islet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from Type 1 diabetes. Diabet Med 28:1028-1033.

Specimen Labelling Procedure