TY - JOUR
T1 - Inter-laboratory variation in DNA damage using a standard comet assay protocol
AU - Forchhammer, Lykke
AU - Ersson, Clara
AU - Loft, Steffen
AU - Möller, Lennart
AU - Godschalk, Roger W L
AU - van Schooten, Frederik J
AU - Jones, George D D
AU - Higgins, Jennifer A
AU - Cooke, Marcus
AU - Mistry, Vilas
AU - Karbaschi, Mahsa
AU - Collins, Andrew R
AU - Azqueta, Amaya
AU - Phillips, David H
AU - Sozeri, Osman
AU - Routledge, Michael N
AU - Nelson-Smith, Kirsty
AU - Riso, Patrizia
AU - Porrini, Marisa
AU - Matullo, Giuseppe
AU - Allione, Alessandra
AU - Steepnik, Maciej
AU - Komorowska, Magdalena
AU - Teixeira, João Paulo
AU - Costa, Solange
AU - Corcuera, Laura-Ana
AU - López de Cerain, Adela
AU - Laffon, Blanca
AU - Valdiglesias, Vanessa
AU - Møller, Peter
PY - 2012/11
Y1 - 2012/11
N2 - There are substantial inter-laboratory variations in the levels of DNA damage measured by the comet assay. The aim of this study was to investigate whether adherence to a standard comet assay protocol would reduce inter-laboratory variation in reported values of DNA damage. Fourteen laboratories determined the baseline level of DNA strand breaks (SBs)/alkaline labile sites and formamidopyrimidine DNA glycosylase (FPG)-sensitive sites in coded samples of mononuclear blood cells (MNBCs) from healthy volunteers. There were technical problems in seven laboratories in adopting the standard protocol, which were not related to the level of experience. Therefore, the inter-laboratory variation in DNA damage was only analysed using the results from laboratories that had obtained complete data with the standard comet assay protocol. This analysis showed that the differences between reported levels of DNA SBs/alkaline labile sites in MNBCs were not reduced by applying the standard assay protocol as compared with the laboratory's own protocol. There was large inter-laboratory variation in FPG-sensitive sites by the laboratory-specific protocol and the variation was reduced when the samples were analysed by the standard protocol. The SBs and FPG-sensitive sites were measured in the same experiment, indicating that the large spread in the latter lesions was the main reason for the reduced inter-laboratory variation. However, it remains worrying that half of the participating laboratories obtained poor results using the standard procedure. This study indicates that future comet assay validation trials should take steps to evaluate the implementation of standard procedures in participating laboratories.
AB - There are substantial inter-laboratory variations in the levels of DNA damage measured by the comet assay. The aim of this study was to investigate whether adherence to a standard comet assay protocol would reduce inter-laboratory variation in reported values of DNA damage. Fourteen laboratories determined the baseline level of DNA strand breaks (SBs)/alkaline labile sites and formamidopyrimidine DNA glycosylase (FPG)-sensitive sites in coded samples of mononuclear blood cells (MNBCs) from healthy volunteers. There were technical problems in seven laboratories in adopting the standard protocol, which were not related to the level of experience. Therefore, the inter-laboratory variation in DNA damage was only analysed using the results from laboratories that had obtained complete data with the standard comet assay protocol. This analysis showed that the differences between reported levels of DNA SBs/alkaline labile sites in MNBCs were not reduced by applying the standard assay protocol as compared with the laboratory's own protocol. There was large inter-laboratory variation in FPG-sensitive sites by the laboratory-specific protocol and the variation was reduced when the samples were analysed by the standard protocol. The SBs and FPG-sensitive sites were measured in the same experiment, indicating that the large spread in the latter lesions was the main reason for the reduced inter-laboratory variation. However, it remains worrying that half of the participating laboratories obtained poor results using the standard procedure. This study indicates that future comet assay validation trials should take steps to evaluate the implementation of standard procedures in participating laboratories.
KW - Calibration
KW - Comet Assay
KW - DNA Damage
KW - DNA-Formamidopyrimidine Glycosylase
KW - Endpoint Determination
KW - Humans
KW - Laboratories
KW - Leukocytes, Mononuclear
KW - Linear Models
U2 - 10.1093/mutage/ges032
DO - 10.1093/mutage/ges032
M3 - Journal article
C2 - 22844078
SN - 0267-8357
VL - 27
SP - 665
EP - 672
JO - Mutagenesis
JF - Mutagenesis
IS - 6
ER -