Personalized reference intervals based on biological variation for serum bone turnover markers in healthy older adults

Abstract Objectives The clinical utility of serum bone turnover markers (BTMs) in managing osteoporosis in the elderly is constrained by the absence of personalized reference intervals (prRI) based on biological variation (BV). Methods This longitudinal study tracked monthly serum levels of β-CTX (C-terminal cross-linking telopeptide of type I collagen), procollagen type I N-propeptide (PINP), osteocalcin (OC), parathyroid hormone (PTH), and 25-hydroxyvitamin D (25(OH)D) over six months in 40 healthy elderly participants aged 60–75 years (16 males and 24 females). The study calculated estimates of within-subject BV (CV I ), between-subject BV (CV G ), within-person BV (CV P ), analytical variation (CV A ), and reference change values (RCVs).These parameters were subsequently used to establish the personalized reference interval (prRI). Results Considerable variability in CV I , CV P , and CV G was observed for BTMs in older adults. Gender differences in baseline concentrations were observed for PINP, OC, and 25(OH)D (p