From the Guidelines
C-telopeptide is a biomarker for bone turnover, specifically indicating the rate of bone resorption (breakdown), and is commonly measured through a blood test to assess bone health and monitor treatment effectiveness for conditions like osteoporosis.
Definition and Purpose
C-telopeptide is a protein fragment released into the bloodstream when bone is broken down during the natural process of bone remodeling. It serves as an indicator of the rate of bone resorption, providing valuable information about dynamic bone metabolism that static bone density scans cannot capture 1.
Clinical Utility
The serum C-terminal telopeptide (CTX) test is used to assess bone health and monitor treatment effectiveness for conditions like osteoporosis. Normal C-telopeptide levels vary by age and gender, but elevated levels suggest increased bone breakdown, which may indicate conditions such as osteoporosis, Paget's disease, or bone metastases 2.
Monitoring and Treatment
Conversely, decreased levels typically reflect successful treatment with bone-preserving medications like bisphosphonates. The test is particularly useful for monitoring response to osteoporosis treatments, as effective therapy should reduce C-telopeptide levels, indicating a slowdown in bone loss 3.
Key Points
- C-telopeptide is a biomarker for bone resorption
- It is measured through a blood test to assess bone health and monitor treatment effectiveness
- Elevated levels indicate increased bone breakdown, while decreased levels reflect successful treatment
- The test provides valuable information about dynamic bone metabolism that static bone density scans cannot capture 1.
From the FDA Drug Label
In clinical studies, treatment with 60 mg of Prolia resulted in reduction in the bone resorption marker serum type 1 C-telopeptide (CTX) by approximately 85% by 3 days, with maximal reductions occurring by 1 month.
- C-telopeptide (CTX) is a bone resorption marker.
- It is a marker used to measure the level of bone resorption in the body.
- In the context of denosumab treatment, CTX levels are used to assess the effectiveness of the treatment in reducing bone resorption 4.
From the Research
Definition of C-telopeptide
- C-telopeptide, also known as C-terminal telopeptide, is a marker of bone resorption 5, 6.
- It is a fragment of type I collagen that is generated by osteoclastic bone resorption 7, 8.
Measurement and Significance
- The measurement of C-telopeptide is useful for the clinical investigation of patients with osteoporosis 5, 6.
- It is used as a reference marker of bone resorption, along with other markers such as N-terminal propeptide of type I procollagen (PINP) 5, 6.
- C-telopeptide levels can be affected by various factors, including feeding, recent fracture, and treatment with anti-osteoporotic therapies 5.
Applications in Research and Clinical Practice
- C-telopeptide has been used in research studies to measure bone resorption in animal models, such as mice and rats 7, 8.
- It has also been used in clinical practice to monitor the response to anti-osteoporotic therapies and to assess compliance with treatment 5, 6.
- The measurement of C-telopeptide can provide valuable information on bone metabolism and can be used to identify patients at high risk of fracture 6.