1. Diurnal, Weekly, and Long-Time Variation in Serum Concentrations of YKL-40 in Healthy Subjects
- Author
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Gine Kollerup, Ib Jarle Christensen, Tine Lottenburger, Jensen Je, Hans Jørgen Nielsen, Mads N Svendsen, and Julia S. Johansen
- Subjects
Adult ,Male ,musculoskeletal diseases ,medicine.medical_specialty ,Adolescent ,Epidemiology ,Intraclass correlation ,Coefficient of variation ,Enzyme-Linked Immunosorbent Assay ,Physical exercise ,Gastroenterology ,Adipokines ,Reference Values ,Lectins ,Neoplasms ,Internal medicine ,Biomarkers, Tumor ,medicine ,Humans ,Chitinase-3-Like Protein 1 ,Exercise ,Aged ,Glycoproteins ,business.industry ,Diurnal temperature variation ,Healthy subjects ,Reproducibility of Results ,Cancer ,Middle Aged ,Prognosis ,medicine.disease ,Confidence interval ,Circadian Rhythm ,Endocrinology ,Oncology ,Linear Models ,Biomarker (medicine) ,Female ,business - Abstract
Serum YKL-40 is a potential biomarker of prognosis in cancer patients, but assessment of serum YKL-40 requires knowledge of its normal variation. In this study, we evaluated diurnal, weekly, and long-term variation in serum YKL-40 in healthy subjects using a commercial ELISA. The intra-assay coefficient of variation was ≤5.0% and interassay ≤10.2%. Systematic changes in diurnal measurements of serum YKL-40 could not be shown. Physical exercise for 20 min had no effect on serum YKL-40. The within-subject coefficient of variation, including variation over time and interassay, was 28.8% and 30.2% over a period of 2 and 3 years, and the intraclass correlation coefficients were 72.4% and 72.2%, indicating reasonable reliability of serum YKL-40 measurements. The 95% confidence limits for the difference between two measurements (same subject), including interassay variation, were a 52% reduction and a 109% increase in serum YKL-40. These studies show that relatively small variation is found in serum YKL-40 in healthy subjects. However, a single measurement of serum YKL-40 from an individual may not have a prognostic value, and serum YKL-40 alone cannot be a good biomarker for cancer because serum YKL-40 can be elevated in patients with other diseases characterized by inflammation and tissue remodeling. (Cancer Epidemiol Biomarkers Prev 2008;17(10):2603–8)
- Published
- 2008