
Carina Törn
Coordinator

Calcium addition to EDTA plasma eliminates falsely positive results in the RSR GADAb ELISA
Author
Summary, in English
BACKGROUND: The RSR ELISAs for GADAb and IA-2Ab are now widely used but due to a considerable number of falsely positive GADAb results obtained with EDTA plasma, it is recommended that only serum samples are run in these two assays. However, as EDTA plasma is often the preferred sample type in Europe we have assessed the possibility that adding Ca(2+) to plasma would reduce the number of falsely positive results. METHODS: Antibody positive as well as antibody negative diabetic subjects were included in the study (n=80). Serum and EDTA plasma were collected from the same subjects at the same occasion. Samples were divided into three groups; sera, EDTA plasma and EDTA plasma+Ca(2+). ELISA kits were supplied by RSR((R)) Ltd and performed according to the manufacturers instructions. RESULTS: GADAb analyses with plasma showed a markedly increased prevalence of GADAb positive subjects (81%) compared to sera (36%), indicating falsely positive results with plasma. Addition of Ca(2+) reduced the number of GADAb positive results to the same number obtained with serum. IA-2Ab positivity was not different between sera and plasma. CONCLUSION: EDTA plasma can be used in the RSR GADAb and IA-2Ab ELISAs if Ca(2+) is added prior to assay.
Department/s
- Medicine, Lund
- Celiac Disease and Diabetes Unit
Publishing year
2008
Language
English
Pages
130-134
Publication/Series
Clinica Chimica Acta
Volume
388
Issue
1-2
Document type
Journal article
Publisher
Elsevier
Topic
- Clinical Laboratory Medicine
Status
Published
Research group
- Diabetes and Celiac Unit
ISBN/ISSN/Other
- ISSN: 0009-8981