Limits...
Variability of exhaled breath condensate leukotriene B4 and 8-isoprostane in COPD patients.

Borrill ZL, Starkey RC, Singh SD - Int J Chron Obstruct Pulmon Dis (2007)

Bottom Line: Group mean differences for WD and BD were small and statistically nonsignificant.WA variability and group mean changes were small.However, we observed considerable WD and BD variability for these biomarkers.

View Article: PubMed Central - PubMed

Affiliation: Medicines Evaluation Unit, Langley Building, Manchester University Wythenshawe Hospital, Manchester M23 9LT, UK. zborrill@meu.org.uk

ABSTRACT
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.

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Bland Altman plots for (A) within day and (B) between day variability of EBC LTB4. Mean LTB4 plotted against difference between 2 EBC samples taken 1 hour and 1 week apart.Abbreviations: EBC, exhaled breath condensate; LTB4, leukotriene B4.
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f2-copd-2-71: Bland Altman plots for (A) within day and (B) between day variability of EBC LTB4. Mean LTB4 plotted against difference between 2 EBC samples taken 1 hour and 1 week apart.Abbreviations: EBC, exhaled breath condensate; LTB4, leukotriene B4.

Mentions: The coefficients of variation are shown in Table 1; the WA coefficient of variation for both LTB4 and 8-isoprostane was lower than the corresponding values for WD and BD variability. The repeatability coefficient for the 8-isoprostane assay was 18.6 pg/ml and for the LTB4 assay was 13.2 pg/ml. Group mean differences for WD and BD changes were small (Table 2). In contrast, the limits of agreement for WD and BD variability were large, demonstrating that levels of LTB4 and 8-isoprostane can change markedly in some individuals even within 1 h (Table 2; Figure 1, 2). Limits of agreement for current smokers were in some cases wider than those for ex-smokers for both 8-isoprostane and LTB4 (Table 3).


Variability of exhaled breath condensate leukotriene B4 and 8-isoprostane in COPD patients.

Borrill ZL, Starkey RC, Singh SD - Int J Chron Obstruct Pulmon Dis (2007)

Bland Altman plots for (A) within day and (B) between day variability of EBC LTB4. Mean LTB4 plotted against difference between 2 EBC samples taken 1 hour and 1 week apart.Abbreviations: EBC, exhaled breath condensate; LTB4, leukotriene B4.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2692117&req=5

f2-copd-2-71: Bland Altman plots for (A) within day and (B) between day variability of EBC LTB4. Mean LTB4 plotted against difference between 2 EBC samples taken 1 hour and 1 week apart.Abbreviations: EBC, exhaled breath condensate; LTB4, leukotriene B4.
Mentions: The coefficients of variation are shown in Table 1; the WA coefficient of variation for both LTB4 and 8-isoprostane was lower than the corresponding values for WD and BD variability. The repeatability coefficient for the 8-isoprostane assay was 18.6 pg/ml and for the LTB4 assay was 13.2 pg/ml. Group mean differences for WD and BD changes were small (Table 2). In contrast, the limits of agreement for WD and BD variability were large, demonstrating that levels of LTB4 and 8-isoprostane can change markedly in some individuals even within 1 h (Table 2; Figure 1, 2). Limits of agreement for current smokers were in some cases wider than those for ex-smokers for both 8-isoprostane and LTB4 (Table 3).

Bottom Line: Group mean differences for WD and BD were small and statistically nonsignificant.WA variability and group mean changes were small.However, we observed considerable WD and BD variability for these biomarkers.

View Article: PubMed Central - PubMed

Affiliation: Medicines Evaluation Unit, Langley Building, Manchester University Wythenshawe Hospital, Manchester M23 9LT, UK. zborrill@meu.org.uk

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus