Disagreement between ion selective electrode direct and indirect sodium measurements: estimation of the problem in a tertiary referral hospital

Dimeski, Goce, Morgan, Thomas J., Presneill, Jeffrey J. and Venkatesh, Balasubramanian (2012) Disagreement between ion selective electrode direct and indirect sodium measurements: estimation of the problem in a tertiary referral hospital. Journal of Critical Care, 27 3: 326.e9-326.e16. doi:10.1016/j.jcrc.2011.11.003

Attached Files (Some files may be inaccessible until you login with your UQ eSpace credentials)
Name Description MIMEType Size Downloads

Author Dimeski, Goce
Morgan, Thomas J.
Presneill, Jeffrey J.
Venkatesh, Balasubramanian
Title Disagreement between ion selective electrode direct and indirect sodium measurements: estimation of the problem in a tertiary referral hospital
Journal name Journal of Critical Care   Check publisher's open access policy
ISSN 0883-9441
Publication date 2012-06
Sub-type Article (original research)
DOI 10.1016/j.jcrc.2011.11.003
Volume 27
Issue 3
Start page 326.e9
End page 326.e16
Total pages 8
Place of publication Maryland Heights, MO, U.S.A.
Publisher W.B. Saunders Co.
Collection year 2013
Language eng
Formatted abstract
Purpose: We estimated the proportion of indirect ion selective electrode (ISE) plasma sodium analyses in intensive care unit (ICU) and hospital wide, exhibiting important disagreement with direct ISE results in relation to abnormal plasma protein concentrations.
Materials and Methods: Direct and indirect ISE plasma sodium measurements were performed on 346 clinical specimens selected to reflect low, normal, or high total protein concentrations. Important intermethod disagreement was defined as |4| mmol/L or higher. Results were extrapolated to a 3-month laboratory series of 48 033 indirect ISE assays, including 2877 samples from intensive care.
Results: Intermethod sodium disagreement at |4| mmol/L or higher was predicted for 25% of ICU samples. Almost all (97%) occurred in hypoproteinemic samples where indirect tended to exceed direct ISE estimates. Hospital wide, such disagreement was projected to occur in 8% of samples, of which the majority (70%) were also hypoproteinemic.
Conclusions: Important disagreement between indirect and direct ISE sodium measurements may exist in up to 1 in 4 ICU specimens and 1 in 12 hospital-wide samples. The main problem is indirect ISE overestimation associated with hypoproteinemia, potentially leading to misclassifications of pseudohypernatremia and pseudonormonatremia. We recommend that hospital laboratories consider standardization using direct ISE sodium measurement.
Keyword Direct
Error
Indirect
Ion selective
Protein
Sodium
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Medicine Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 3 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 20 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Mon, 30 Jul 2012, 18:29:25 EST by Matthew Lamb on behalf of School of Medicine