Requirements for improving quality in the measurement of bone markers

BACKGROUND: A number of biochemical assays readily detect molecules released from the bone matrix and collagen degradation in both serum and urine specimens. The variability of bone biochemical markers is still an issue of practical concern limiting their wider clinical use, and compromising the management of the individual patient. The aim of the present study was to define quality specifications of bone markers measurement in the total testing process. METHODS: The different sources of biological variability of biochemical bone marker were assessed according to the current knowledge and categorized as pre-analytical, intra-analytical and post-analytical. RESULTS: The identification of factors influencing bone marker measurements allowed recommendations to be made for decreasing pre- and intra-analytical variation in order to improve laboratory performance. The assessment of post-analytical sources of variation, moreover, involves the practical use of bone markers in identifying individual women at risk of fractures and the identification of non-responders, providing adequate limit value, least significant change value or optimal threshold of bone marker change. CONCLUSIONS: Laboratory services may improve the potential clinical applications of biochemical markers of bone remodeling by improving method standardization, defining and reducing pre-analytical and analytical variables and providing reports that specify analytical and biological variation or cut-off values, thus facilitating data interpretation or reports.