Bone turnover markers in osteoporosis: a common statement on their use of the Society for Metabolic Bone Diseases within the Czech Medical Association of J.E. Purkyne (SMBD CzMA JEP) and the Czech Society of Clinical Biochemistry within the Czech Medical Association of J.E. Purkyne (CSCB CzMA JEP)
Abstract
The publication is a joint position of the Czech Society of Clinical Biochemistry and the Society for Metabolic Skeletal Diseases on the use of bone turnover markers in patients with osteoporosis. It is recommended to use PINP (Procollagen type I N-terminal propeptide) in μg/L as a marker of bone formation and CTX-I (C-terminal telopeptide of type I collagen) in ng/L as a marker of bone resorption.
Blood sampling should be performed after an over-night fasting, an enormous physical load 24 hours prior to collection should be also avoided. Always take blood samples between hours 7:00 and 10:00 in the morning.
Both serum and EDTA-plasma are acceptable. EDTA-plasma is preferable when CTX-I cannot be processed within 8 hours.
PINP is not an optimal parameter in patients monitoring treated by corticoids, except anabolic therapy monitoring. Harmonised reference limits were recommended to unify their interpretation.
For Roche systems we suggested basal reference range (CTX-I 100-600 ng/L for women, 70-700 ng/L for men; PINP 20-70 µg/L for both men and women), upper pathological limit (CTX-I 1 000 ng/L for women, 850 ng/L for men; PINP 100 µg/L for both men and women) For IDS systems we suggested to use basal reference limit (CTX-I 50-670 ng/L in women, 90-780 ng/L in men; PINP 20-75 µg/L in women, 20-80 µg/L in men), upper pathological limit (CTX-I 1 050 ng/L in women, 850 ng/L in men; PINP 100 µg/L in both men and women). For therapy monitoring a 25% change in serum CTX-I and PINP values is defined as LSC (least significant change), or in absolute values it means 100 ng/L change of serum CTX-I and 10 µg/L change for PINP.