Reference limits for GAD65 and IA-2 autoantibodies by chemiluminescence immunoassay in Northern European adults and children

Abstract

The GAD65 and IA-2 antibodies (Abs) are biomarkers of the development of type 1 diabetes mellitus (T1DM) in both children and adults. The upper reference limit for the autoantibodies made by the manufacture was established on an adult Chinese population. Here, we established upper reference limits for Northern European adults and children in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines. Serum samples from healthy Danish children (0–18 years) and adults (18–70 years) were analysed for GAD65Ab and IA-2Ab using MAGLUMI 800 Chemiluminescence Immunoassay (CLIA). The Kruskal–Wallis test was used for evaluating differences between gender and age groups. No gender or age differences were found for neither GAD65Ab nor IA-2Ab, and a combined upper reference limit for both children and adults could be established. An upper reference limit of 5.1 IU/mL was defined for GAD65Ab and 11.5 U/mL for IA-2Ab. Our results showed a substantial discrepancy with the reference limits established by the manufacturer.

Keywords:

• Adult
• antibodies
• diabetes mellitus
• GAD65
• ICA512 autoantibody
• paediatrics
• reference values

Acknowledgements

Laboratory technician Tine Kusk is acknowledged for technical and logistic assistance.

Disclosure statement

None. The funding organisations played no role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.

Additional information

Funding

The study was supported by the Danish Central Region, Department of Clinical Biochemistry. Snibe Diagnostic delivered kits for GAD65Ab and IA-2Ab measurements free of charge.