A simple screening method for individuals at risk of developing type 1 diabetes: measurement of islet cell autoantibodies (GADA, IA-2A, and IAA) on dried capillary blood spots collected on filter paper.
There is limited information regarding the use of dried capillary blood spots collected on a filter paper (FP) to test for islet cell antibodies. The aim of this study was to validate the use of dried capillary blood spots collected on a FP for the analysis of islet cell antibodies. FP eluates were tested using both single and combined assay for antibodies to glutamic acid decarboxylase (GADA) and/or to the protein tyrosine phosphatase like IA-2 (IA-2A), and a single assay for antibodies to insulin (IAA). The results were compared with those of serum assays. Ninety-one subjects were studied. Forty had Type 1 diabetes mellitus (T1DM) and 51 were first-degree relatives (FDR) of patients with T1DM. The GADA and IA-2A were measured by radio-binding assays, which utilize 35S-labeled GAD65 and IA-2. IAA was measured by a microtiter plate assay using 125I-labeled insulin. Twenty-six of those with T1DM (65%) and 5 of the FDRs (10%) had at least 1 positive test on the single serum assays. The FP combi-assay for GADA and IA-2A had 97.8% concordance rate when compared with serum single assays for GADA and IA-2A. The concordance rate for individual assays were 96.7% for GADA, and 100% for both IA-2A and IAA There was significant correlation of the antibody levels between FP and serum specimen for all 3 antibodies. We conclude that antibody screening performed using dried capillary blood spots collected on a FP correlates well with serum assays, and provides an easy alternative for population screening.
Department of Endocrinology, Diabetes and Metabolism, Cleveland Clinic, Cleveland, OH, USA.
E S
ES
Siraj
D G
DG
Rogers
M K
MK
Gupta
S S K
SS
Reddy
D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000175:diagnosis*; D059788:Dried Blood Spot Testing / Q000379:methods*; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006801:Humans; D007330:Insulin Antibodies / Q000097:blood; D008297:Male; D008875:Middle Aged; D055815:Young Adult
D001323:Autoantibodies; C096322:ICA512 autoantibody; D007330:Insulin Antibodies; C024211:islet cell antibody; D005968:Glutamate Decarboxylase