Multi-centre observational study of spurious hyperkalaemia due to EDTA contamination.
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Authors
Cornes, Michael P
Redpath, Mark
Waldron, Jenna Louise
Ford, Clare
Gama, Rousseau
Issue Date
2010-11-01
Journal
Type
Multicentre Study
Observational Study
Peer-Reviewed Publication
Observational Study
Peer-Reviewed Publication
Keywords
Blood preservation
Cross Sectional Study
Drug contamination
Edetic acid
False positive reactions
Hyperkalemia
Potassium
kEDTA
Potassium ethylenediamine tetraacetic acid (K-EDTA)
Cross Sectional Study
Drug contamination
Edetic acid
False positive reactions
Hyperkalemia
Potassium
kEDTA
Potassium ethylenediamine tetraacetic acid (K-EDTA)
Journal Title
Clinical Laboratory
Volume
56
Issue
11-12
Begin page
597
End page
599
DOI
Abstract
Background: A multi-centre observational study investigating the prevalence of spurious hyperkalaemia due to potassium ethylenediaminetetraacetic acid (kEDTA) contamination.
Methods: Serum EDTA was measured in anonymised serum samples with a serum potassium > 6.0 mmol/L collected over a one month period in five different hospital laboratories. Two of the participating laboratories routinely screen all hyperkalaemic samples for EDTA contamination.
Results: EDTA contamination was present in 4.1% (range 1.2%-6.7%) of hyperkalaemic samples. In three laboratories, without routine EDTA screening, 50% "EDTA contaminated" were identified by laboratory staff, the remaining 50% samples were undetected and reported as genuine hyperkalaemia. In these laboratories, EDTA was not measurable in 2 samples reported as "EDTA contaminated".
Conclusions: Spurious hyperkalaemia due to kEDTA contamination is relatively common. Education regarding correct blood collection technique offers the best strategy in preventing EDTA sample contamination. Gross kEDTA contamination is easily identified by laboratory staff in samples with marked unexpected hyperkalaemia and hypocalcaemia. Spurious hyperkalaemia due to modest kEDTA contamination may only be confidently detected by measurement of serum EDTA.
Citation
Cornes MP, Davidson F, Darwin L, Gay C, Redpath M, Waldron JL, Ford C, Gama R. Multi-centre observational study of spurious hyperkalaemia due to EDTA contamination. Clin Lab. 2010;56(11-12):597-9. PMID: 21141447.