Comparison of Measurements of Autoantibodies to Glutamic Acid Decarboxylase and Islet Antigen-2 in Whole Blood Eluates from Dried Blood Spots Using the RSR-Enzyme Linked Immunosorbent Assay Kits and In-House Radioimmunoassays

Abstract EN

To evaluate the performance of dried blood spots (DBSs) with subsequent analyses of glutamic acid decarboxylase (GADA) and islet antigen-2 (IA-2A) with the RSR-ELISAs, we selected 80 children newly diagnosed with type 1 diabetes and 120 healthy women.

DBSs from patients and controls were used for RSR-ELISAs while patients samples were analysed also with in-house RIAs.

The RSR-ELISA-GADA performed well with a specificity of 100%, albeit sensitivity (46%) was lower compared to in RIA (56%; P=.008).

No prozone effect was observed after dilution of discrepant samples.

RSR-ELISA-IA-2A achieved specificity of 69% and sensitivity was lower (59%) compared with RIA (66%; P<.001).

Negative or low positive patients and control samples in the RSR-ELISA-IA-2A increased after dilution.

Eluates from DBS can readily be used to analyse GADA with the RSR-ELISA, even if low levels of autoantibodies were not detected.

Some factor could disturb RSR-ELISA-IA-2A analyses.