CTX Beta-CrossLaps
The CTX test (also called Beta-CrossLaps test ) is a blood test used to measure bone breakdown. It measures the concentration of C-terminal telopeptide of type I collagen (CTX), a degradation product of collagen released during the breakdown of bone tissue.
What is the CTX test used for?
Osteoporosis: to assess how active the bone breakdown process is.
Evaluation of treatment: in people taking anti- osteoporosis drugs (such as bisphosphonates), to see if the treatment is effective.
Increased risk of bone fractures: in postmenopausal women, people with low body weight, side effects of medications such as corticosteroids, or in men with testosterone deficiency.
Bone metastases: sometimes also in oncology, to monitor whether cancer has spread to the bone.
Important to know
The CTX value varies with the rhythm of the day: it is highest in the morning sober. Therefore, blood sampling should be done in the morning between 7:30 and 8:30 a.m. sober (after 12 hours of fasting).
is often determined along with other markers of bone metabolism, such as P1NP (a marker of bone remodeling).
Sample results (for reference only):
Low CTX: may indicate minimal bone resorption (a positive sign of successful osteoporosis treatment).
High CTX: may indicate active bone resorption (for example, in untreated osteoporosis or certain diseases).
