Document Detail


Preanalytical variables in measurement of free (ionized) calcium in lithium heparin-containing blood collection tubes.
MedLine Citation:
PMID:  19361462     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Measurements of free (ionized) calcium (iCa) are increasingly requested in patient care locations where immediate analysis is unavailable. Evacuated blood collection tubes containing lithium heparin and gel separator material are widely used in clinical laboratories, but little information is available on the effects of these tubes or of delay prior to analysis on the concentration or stability of iCa. METHODS: We collected blood from volunteers into lithium-heparin tubes (PST, Vacutainer PST, BD Pre-Analytic Systems) of multiple lots and into electrolyte-balanced heparin syringes (Portex Dry Heparin, Smiths Medical). iCa was measured (Siemens 1265 blood gas analyzers) immediately and, in PST, at 0-7 h with or without transportation of the tubes from remote sites. RESULTS: The mean difference of free calcium results in the PST tubes and electrolyte-balanced syringes was -0.08 (95% confidence interval -0.17 to 0.012) mmol/l, and the SD of the residuals (Sy, x) of the regression was 0.03 mmol/l. There was no detectable lot-to-lot variation in results. Free calcium was stable in tubes at room temperature and at 4 degrees C for at least 7 h with or without transportation. CONCLUSION: iCa measured in the examined blood collection tubes is stable and unaffected by lot-to-lot variation of tubes, but results are slightly lower than with special blood gas syringes.
Authors:
Doris M Haverstick; Louis B Brill; Mitchell G Scott; David E Bruns
Publication Detail:
Type:  Journal Article     Date:  2009-02-04
Journal Detail:
Title:  Clinica chimica acta; international journal of clinical chemistry     Volume:  403     ISSN:  1873-3492     ISO Abbreviation:  Clin. Chim. Acta     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-04-27     Completed Date:  2009-07-06     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  1302422     Medline TA:  Clin Chim Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  102-4     Citation Subset:  IM    
Affiliation:
Department of Pathology, University of Virginia, Charlottesville, VA, United States. dmh2t@virginia.edu
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MeSH Terms
Descriptor/Qualifier:
Blood Specimen Collection / methods*
Calcium / blood*
Heparin*
Humans
Laboratories
Lithium
Temperature
Time Factors
Chemical
Reg. No./Substance:
7439-93-2/Lithium; 7440-70-2/Calcium; 9005-49-6/Heparin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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