How is bone turnover assessed?
Bone is constantly renewed: old tissue is destroyed by osteoclasts, new tissue is created by osteoblasts. Densitometry shows the result of this balance - bone density, but reacts slowly, changes are noticeable only after a year or two. Biochemical markers reflect the process in real time. Osteocalcin is a marker of bone synthesis: it is produced by osteoblasts and partially enters the blood. Its determination is used in osteoporosis to assess the type of bone turnover (high or low turnover), and most importantly, for early control of treatment: a change in the marker after 3-6 months shows whether the therapy is working, long before densitometry confirms it. The indicator depends on the time of day - blood is donated in the morning on an empty stomach.
How to prepare to donate blood
- on an empty stomach 8–12 hours, you can drink water
- Eliminate alcohol and intense exercise per day
- no smoking in an hour
- donate blood before physiotherapy, x-rays and massage
- Take medications in advance by agreeing with your doctor
How to read the result
Reference values depend on the method and equipment of the laboratory, so it is correct to compare results only within the same laboratory. A deviation of a few percent from the normal limit in itself rarely matters - the overall picture and dynamics are important.
The analysis must be interpreted by a doctor: an isolated indicator without a clinical context is often misleading and leads to unnecessary examinations.