Establishing the performance and acceptability of dried blood spot sampling to screen for islet-specific autoantibodies.

BACKGROUND

Islet-specific autoantibodies predate and predict the onset of type 1 diabetes and can be used to screen for presymptomatic disease. Dried blood spots (DBS) offer a convenient and reliable method for community-based capillary sampling requiring low blood volumes compared to venous collection. We aimed to verify the use of DBS for detecting autoantibodies by the ElisaRSR (3-screen) multiplex assay compared to venous sampling and also explore the acceptability of DBS sampling.

METHODS

Paired serum and DBS samples were collected from healthy controls (HC) and individuals with type 1 diabetes on insulin. Validation and verification of a 3-screen Islet cell autoantibody (IA-2A, GADA and ZnT8A) ELISA assay was undertaken for both matrices and compared. Perceived acceptability of DBS testing was explored via semi-structured interviews with parents and professional stakeholders.

RESULTS

Temporally paired serum and DBS samples were collected for 101 individuals with type 1 diabetes (aged 7-73 years) and 22 HC (aged 18-60 years). Performance characteristics were similar for serum and DBS; sensitivity for serum was 86% compared to 89% for DBS and a specificity of 97% for serum compared to 100% for DBS. Parents (n = 38) and stakeholders (n = 25) thought DBS testing offered a minimally invasive, convenient screening test. Parents emphasised choice of screening location, including home and community settings.

CONCLUSIONS

DBS sampling can be used as an alternative to serum for use with the 3-screen assay for general population type 1 diabetes autoantibody screening. DBS sampling appears acceptable to parents and stakeholders.