Applications of an enzyme immunoassay for a new marker of bone resorption (CrossLaps): follow-up on hormone replacement therapy and osteoporosis risk assessment.

An enzyme-linked immunosorbent immunoassay (ELISA) for a new marker of bone resorption (CrossLaps) was evaluated. The ELISA procedure determines degradation products of type I collagen in urine. Values obtained in the ELISA and in pyridinoline by high pressure liquid chromatography were correlated after a correction for creatinine. A high correlation was found (r = 0.77; n = 81). A group of postmenopausal women (n = 180) showed an increase of more than 70% compared to values in premenopausal women (n = 104). Hydroxyproline was increased by 23%, osteocalcin by 52%, pyridinoline by 31%, and deoxypyridinoline by 50%. A highly significant decrease (60.7%) in the CrossLaps values was seen after 12 months in samples from patients receiving hormone replacement therapy compared to a placebo group. The spontaneous bone loss in an untreated group of women was determined by repeated forearm bone mass measurement over 24 months. Baseline values obtained in the CrossLaps ELISA were correlated to the rate of loss, yielding a highly significant r value of -0.61, indicating that CrossLaps might be a useful parameter for assessment of the risk of osteoporosis in postmenopausal women.