Variability of exhaled breath condensate leukotriene B4 and 8-isoprostane in COPD patients.
The reproducibility of exhaled breath condensate (EBC) mediators is not well documented in chronic obstructive pulmonary disease (COPD). This study assessed within assay (WA), within (WD) and between day (BD) reproducibility of EBC leukotriene B4 (LTB4) and 8-isoprostane. Three EBC samples were collected from 24 COPD patients separated by 1 h and 1 wk, to assess WD and BD reproducibility. WA reproducibility was assessed by sample analysis by enzyme immunoassay in triplicate. WA coefficient of variation for LTB4 and 8-isoprostane (18.2% and 29.2%, respectively) was lower than corresponding values for WD (47.7% and 65.3%, respectively) and BD (75.7% and 79.1%, respectively). Repeatability coefficient for 8-isoprostane and LTB4 assays were 18.6 pg/ml and 13.2 pg/ml, respectively. Group mean differences for WD and BD were small and statistically nonsignificant. Using the Bland Altman method, there were wide limits of agreement for WD (-51.6 to 47.2 for 8-isoprostane and -31.8 to 31.4 for LTB4) and BD reproducibility (-61.4 to 75.7 for 8-isoprostane and -29.3 to 38.6 for LTB4). This is the first study to fully report the variability of EBC 8-isoprostane and LTB4 in COPD. WA variability and group mean changes were small. However, we observed considerable WD and BD variability for these biomarkers.
Medicines Evaluation Unit, Langley Building, Manchester University Wythenshawe Hospital, Manchester M23 9LT, UK. zborrill@meu.org.uk
Zoë L
ZL
Borrill
R Cerys
RC
Starkey
S Dave
SD
Singh
D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests; D003627:Data Interpretation, Statistical; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000032:analysis; D005260:Female; D006801:Humans; D007975:Leukotriene B4 / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis*; D015203:Reproducibility of Results
D015415:Biomarkers; D007975:Leukotriene B4; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost