Your browser has javascript turned off or blocked. This will lead to some parts of our website to not work properly or at all. Turn on javascript for best performance.

The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here:

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Default user image.

Carina Törn


Default user image.

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.


  • Kobra Rahmati
  • Åke Lernmark
  • Charlotte Becker
  • Anna Foltyn Zadura
  • Karin Larsson
  • Sten Ivarsson
  • Carina Törn

Summary, in English

BACKGROUND: Glutamic acid decarboxylase antibodies (GADA) and tyrosine phosphatase antibodies (islet antigen-2 antibodies; IA-2A) are used in clinical practise to identify type 1 diabetes. METHODS: GADA and IA-2A were measured with RSR-ELISA kits in samples from 76 newly diagnosed type 1 diabetic children and 120 healthy controls. The aim was to evaluate performance of RSR-ELISA kits for GADA and IA-2A when serum and Ca2+ treated plasma were used. RESULTS: GADA achieved high area under the curve (AUC) both for serum 0.95 (95% CI 0.90-0.99) and for Ca2+ treated plasma 0.95 (95% CI 0.91-0.99). At specificity 98%, sensitivity was 84% for serum and 87% for Ca2+ treated plasma. IA-2A achieved AUC 0.92 (95% CI 0.87-0.97) for serum and 0.94 (95% CI 0.90-0.98) for Ca2+ treated plasma. Using the lowest standard (15 WHO-Units/ml) as cut-off, specificity for serum was 100% and for Ca2+ treated plasma 99% with sensitivity 74% in both cases. Sensitivity was higher in ELISA compared to RIA (74%; p = 0.0080) for GADA measurement and similar for ELISA and RIA IA-2A measurements (76%; p = 0.50). CONCLUSION: Both RSR-ELISAs, GADA and IA-2A showed excellent performance for serum as well as for Ca2+ treated plasma.


  • Diabetes and Celiac Unit
  • Clinical Chemistry, Malmö
  • Paediatric Endocrinology

Publishing year







Clinical Laboratory





Document type

Journal article


Clin Lab. Publications


  • Endocrinology and Diabetes



Research group

  • Diabetes and Celiac Unit
  • Clinical Chemistry, Malmö
  • Paediatric Endocrinology


  • ISSN: 1433-6510