Blood Sciences Test


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

SPECIMEN TYPES:

Clotted blood (1 x 7.5ml) or 500µl serum for GAD, IA-2 and ZnT8 testing only: 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

GAD Positive: >/= 11 U/mL

ZNT8 Positive:

≤ 30 years >/= 65 U/mL

31 – 120 years >/= 10 U/mL

TARGET REPORTING TIME:

2 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 both serum (preferred sample type) and plasma 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

Our Quality Statement for referred work can be found here:  Quality statement May 2019 (41 downloads)

Assayed By

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

  1. 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.
  2. 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.
  3. 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.
  4. 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