TY - JOUR
T1 - External Quality Assurance of Circulating Tumor Cell Enumeration Using the CellSearch (R) System: A Feasibility Study
AU - Kraan, Jaco
AU - Sleijfer, Stefan
AU - Strijbos, Michiel
AU - Ignatiadis, M
AU - Peeters, D
AU - Pierga, JY
AU - Farace, F
AU - Riethdorf, S
AU - Fehm, T
AU - Zorzino, L
AU - Tibbe, AGJ
AU - Maestro, M
AU - Gisbert-Criado, R
AU - Denton, G
AU - de Bono, JS
AU - Dive, C
AU - Foekens, John
AU - Gratama, Jan willem
PY - 2011
Y1 - 2011
N2 - 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 (R) (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' kappa 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. (C) 2010 International Clinical Cytometry Society
AB - 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 (R) (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' kappa 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. (C) 2010 International Clinical Cytometry Society
U2 - 10.1002/cyto.b.20573
DO - 10.1002/cyto.b.20573
M3 - Article
C2 - 21337491
SN - 1552-4949
VL - 80B
SP - 112
EP - 118
JO - Cytometry Part B-Clinical Cytometry
JF - Cytometry Part B-Clinical Cytometry
IS - 2
ER -
