Human and methodological sources of variability in the measurement of urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine

TY - JOUR

T1 - Human and methodological sources of variability in the measurement of urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine

AU - Barregard, Lars

AU - Møller, Peter

AU - Henriksen, Trine

AU - Mistry, Vilas

AU - Koppen, Gudrun

AU - Rossner, Pavel

AU - Sram, Radim J

AU - Weimann, Allan

AU - Poulsen, Henrik E

AU - Nataf, Robert

AU - Andreoli, Roberta

AU - Manini, Paola

AU - Marczylo, Tim

AU - Lam, Patricia

AU - Evans, Mark D

AU - Kasai, Hiroshi

AU - Kawai, Kazuaki

AU - Li, Yun-Shan

AU - Sakai, Kazuo

AU - Singh, Rajinder

AU - Teichert, Friederike

AU - Farmer, Peter B

AU - Rozalski, Rafal

AU - Gackowski, Daniel

AU - Siomek, Agnieszka

AU - Saez, Guillermo T

AU - Cerda, Concha

AU - Broberg, Karin

AU - Lindh, Christian

AU - Hossain, Mohammad Bakhtiar

AU - Haghdoost, Siamak

AU - Hu, Chiung-Wen

AU - Chao, Mu-Rong

AU - Wu, Kuen-Yuh

AU - Orhan, Hilmi

AU - Senduran, Nilufer

AU - Smith, Raymond J

AU - Santella, Regina M

AU - Su, Yali

AU - Cortez, Czarina

AU - Yeh, Susan

AU - Olinski, Ryszard

AU - Loft, Steffen

AU - Cooke, Marcus S

PY - 2013/6/20

Y1 - 2013/6/20

N2 - Aims: Urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) is a widely used biomarker of oxidative stress. However, variability between chromatographic and ELISA methods hampers interpretation of data, and this variability may increase should urine composition differ between individuals, leading to assay interference. Furthermore, optimal urine sampling conditions are not well defined. We performed inter-laboratory comparisons of 8-oxodG measurement between mass spectrometric-, electrochemical- and ELISA-based methods, using common within-technique calibrants to analyze 8-oxodG-spiked phosphate-buffered saline and urine samples. We also investigated human subject- and sample collection-related variables, as potential sources of variability. Results: Chromatographic assays showed high agreement across urines from different subjects, whereas ELISAs showed far more inter-laboratory variation and generally overestimated levels, compared to the chromatographic assays. Excretion rates in timed 'spot' samples showed strong correlations with 24 h excretion (the 'gold' standard) of urinary 8-oxodG (rp 0.67-0.90), although the associations were weaker for 8-oxodG adjusted for creatinine or specific gravity (SG). The within-individual excretion of 8-oxodG varied only moderately between days (CV 17% for 24 h excretion and 20% for first void, creatinine-corrected samples). Innovation: This is the first comprehensive study of both human and methodological factors influencing 8-oxodG measurement, providing key information for future studies with this important biomarker. Conclusion: ELISA variability is greater than chromatographic assay variability, and cannot determine absolute levels of 8-oxodG. Use of standardized calibrants greatly improves intra-technique agreement and, for the chromatographic assays, importantly allows integration of results for pooled analyses. If 24 h samples are not feasible, creatinine- or SG-adjusted first morning samples are recommended.

AB - Aims: Urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) is a widely used biomarker of oxidative stress. However, variability between chromatographic and ELISA methods hampers interpretation of data, and this variability may increase should urine composition differ between individuals, leading to assay interference. Furthermore, optimal urine sampling conditions are not well defined. We performed inter-laboratory comparisons of 8-oxodG measurement between mass spectrometric-, electrochemical- and ELISA-based methods, using common within-technique calibrants to analyze 8-oxodG-spiked phosphate-buffered saline and urine samples. We also investigated human subject- and sample collection-related variables, as potential sources of variability. Results: Chromatographic assays showed high agreement across urines from different subjects, whereas ELISAs showed far more inter-laboratory variation and generally overestimated levels, compared to the chromatographic assays. Excretion rates in timed 'spot' samples showed strong correlations with 24 h excretion (the 'gold' standard) of urinary 8-oxodG (rp 0.67-0.90), although the associations were weaker for 8-oxodG adjusted for creatinine or specific gravity (SG). The within-individual excretion of 8-oxodG varied only moderately between days (CV 17% for 24 h excretion and 20% for first void, creatinine-corrected samples). Innovation: This is the first comprehensive study of both human and methodological factors influencing 8-oxodG measurement, providing key information for future studies with this important biomarker. Conclusion: ELISA variability is greater than chromatographic assay variability, and cannot determine absolute levels of 8-oxodG. Use of standardized calibrants greatly improves intra-technique agreement and, for the chromatographic assays, importantly allows integration of results for pooled analyses. If 24 h samples are not feasible, creatinine- or SG-adjusted first morning samples are recommended.

KW - Adult

KW - Artifacts

KW - Buffers

KW - Deoxyguanosine

KW - Female

KW - Head and Neck Neoplasms

KW - Humans

KW - Male

KW - Middle Aged

KW - Reference Standards

KW - Reproducibility of Results

KW - Sodium Chloride

KW - Solutions

KW - Urinalysis

KW - Young Adult

U2 - 10.1089/ars.2012.4714

DO - 10.1089/ars.2012.4714

M3 - Journal article

C2 - 23198723

SN - 1523-0864

VL - 18

SP - 2377

EP - 2391

JO - Antioxidants and Redox Signaling

JF - Antioxidants and Redox Signaling

IS - 18

ER -