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

Abstract

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.