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Calcium addition to EDTA plasma eliminates falsely positive results in the RSR GADAb ELISA

Nilson, Emma LU ; Ekholm, Birgitte LU ; Rees Smith, B; Törn, Carina LU and Hillman, Magnus LU (2008) In Clinica Chimica Acta 388(1-2). p.130-134
Abstract
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... (More)
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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Clinica Chimica Acta
volume
388
issue
1-2
pages
130 - 134
publisher
Elsevier
external identifiers
  • pmid:18023278
  • wos:000252770800021
  • scopus:37249029951
ISSN
0009-8981
DOI
10.1016/j.cca.2007.10.021
language
English
LU publication?
yes
id
d6c6a0db-6461-4abf-aa8b-829a7bd6cd47 (old id 1142381)
date added to LUP
2008-08-05 13:41:16
date last changed
2017-04-16 03:36:10
@article{d6c6a0db-6461-4abf-aa8b-829a7bd6cd47,
  abstract     = {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.},
  author       = {Nilson, Emma and Ekholm, Birgitte and Rees Smith, B and Törn, Carina and Hillman, Magnus},
  issn         = {0009-8981},
  language     = {eng},
  number       = {1-2},
  pages        = {130--134},
  publisher    = {Elsevier},
  series       = {Clinica Chimica Acta},
  title        = {Calcium addition to EDTA plasma eliminates falsely positive results in the RSR GADAb ELISA},
  url          = {http://dx.doi.org/10.1016/j.cca.2007.10.021},
  volume       = {388},
  year         = {2008},
}