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Title
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External quality assurance of circulating tumor cell enumeration using the CellSearch® system : a feasibility study
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Author
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Abstract
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| Background: Circulating tumor cells (CTCs) are cells that have detached from solid tumors and entered the blood. CTCs can be detected, among others, by semi-automated immunomagnetic enrichment and image cytometry using CellSearch® (Veridex, Raritan, NJ). We studied the feasibility of external quality assurance (EQA) of the entire CellSearch procedure from blood draw to interpretation of results in multiple laboratories. Methods: Blood samples from six cancer patients and controls were distributed to 14 independent laboratories to test between-laboratory, between-assay, and between-instrument variation. Additionally, between-operator variability was assessed through the interpretation of blinded images of all blood samples on a website. Results: Shipment and storage of samples had no influence on CTC values. Between-instrument (coefficient of variation (CV) < 12%) and between-assay variation was low (CV ≤ 20%), indicating high reproducibility. However, between-laboratory CV ranged from 45 to 64%. Although inter-operator agreement on image interpretation (Fleiss' κ statistics) ranged from substantial to almost perfect, image interpretation, particularly of samples containing high numbers of apoptotic cells, was the main contributor to between-laboratory variation. Conclusions: This multicenter study shows the feasibility of an EQA program for CTC detection in patient samples, and the importance of continuation of such a program for the harmonization of CTC enumeration. © 2010 International International Clinical Cytometry Society |
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Language
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English
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Source (journal)
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Cytometry: part B: clinical cytometry. - New York, 2003, currens
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Publication
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New York
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2011
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ISSN
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1552-4949
[print]
1552-4957
[online]
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DOI
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10.1002/CYTO.B.20573
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Volume/pages
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80
:2
(2011)
, p. 112-118
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ISI
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000287891200006
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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