Bone turnover markers adjustment

A method for correcting a concentration of a bone turnover marker, selected from the list of serum bone-specific alkaline phosphatase, serum osteocalcin, serum type 1 procollagen, serum collagen type 1 cross-linked C-telopeptide, and tartrate-resistant acid phosphatase 5b, to obtain an adjusted value which gives an indication of an individual's bone health status or amount of changes occurred over time or by treatment, the method comprising:

• obtaining the concentration of the bone turnover marker of a sample, correcting the obtained concentration using a mathematical model which comprises at least three factors, different from the bone health status, such that for the adjusted value variabilities in the concentration of the bone turnover marker, that are caused by the at least three factors, are substantially filtered out by the mathematical model;
• wherein the at least three factors are selected from a list comprising age, smoking, alcohol, history of fracture, osteoporosis related drugs, physical activity, taking corticosteroids for more than three months, renal disease, liver disease, type 2 diabetes mellitus, thyroid disorder, menopausal status, menstrual cycle, years after menopause, gender, blood sampling time and fasting;
• and wherein the model at least comprises the following adjustment:
• y=y0(eβ1X1)(eβ2X2) . . . (eβkXk)=y0eΣiβiXi
• and wherein y is the adjusted bone turnover marker, y0 is the mean-measured bone turnover marker across all patients in a database, βi is the estimated coefficient for factor xi, and k is the number of factors.