Reproducibility of measurement techniques used for creatine kinase, interleukin-6 and high-sensitivity C-reactive protein determination over a 48 h period in males and females

ABSTRACT

To examine the reproducibility of three measurement techniques used to determine creatine kinase, interleukin-6 and high-sensitivity C-reactive protein, 50 participants had blood samples taken on two occasions. Fingertip plasma samples were analysed using the Reflotron for CK determination. Venous blood samples collected into serum separator tubes were used for IL-6 and hs-CRP analyses. IL-6 was measured using an enzyme linked immune assay development kit. The hs-CRP was measured by an in-house ELISA method. Dependent t-tests showed no systematic bias between samples. The interdian CV was 20.0% for CK, 15.3% for IL-6 and 44.2% for hs-CRP. The intraclass correlation coefficient was 0.90 for CK, 0.98 for IL-6 and 0.70 for hs-CRP. The 95% limits of agreement were −69.7 to 63.5 IU/L for CK, −1.48 to 1.80 pg/ml for IL-6 and −1.10 to 0.91 µg/L for hs-CRP. The results demonstrate low absolute reproducibility, which may obscure a true experimental effect.

KEYWORDS:

• Exercise induced muscle damage
• reliability
• biomarkers
• cytokines
• inflammation

Acknowledgements

The authors would like to thank the University of Hull, Department of Sport, Health and Exercise Science for the support and opportunity to conduct this study. The authors would also like to thank the volunteers for participation in this study.

Conflicts of interest

The authors declare that this research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.