Contents
The C-terminal cross-linked telopeptide of the type I collagen alpha chain exists in two isomeric forms: and ß. It is formed as a result of bone resorption under the influence of osteoclast activity. The indications for the determination of this peptide include primary and secondary osteoporosis as well as the suspicion of neoplastic bone metastases.
What is Ctx (C-terminal cross-linked telopeptide of type I collagen alpha chain)?
Ctx is briefly a biochemical indicator of bone remodeling. Its formation occurs as a result of collagen breakdown and the action of osteoclast cells, which at the same time stimulate the resorption of bone tissue. Testing the C-terminal cross-linked telopeptide of type I collagen alpha chain is used, among other things, in the diagnosis of bone diseases.
Warning: The C-terminal cross-linked telopeptide of the type I collagen alpha chain is present in all tissues containing type I collagen with the presence of pyridinoline cross-links.
When do we test the C-terminal cross-linked telopeptide of the type I collagen alpha chain?
The most common indications for the test are presented below.
1. Increased bone turnover (intensification of osteolysis processes in hyperparathyroidism and thyroid gland).
2. Suspicion of neoplastic bone metastases.
3. Primary and secondary osteoporosis.
4. Metabolic diseases of bone tissue (Paget’s disease, adynamic bone disease).
Material for Ctx test: serum, daily collection of urine (urine should be collected in a container around the clock – skip the first micturition, collect the next one for the whole day and the first portion of urine on the next day).
Preparation for the test: on an empty stomach (at least 8 hours).
The course of the Ctx study: one-time blood sampling from a vein in the arm.
Time to wait for the Ctx result: 1 Day.
Standards for the Ctx test:
a) serum
– premenopausal women – less than 4000 pmol / l,
– postmenopausal women – less than 7000 pmol / l,
– kids – 7500 ± 5000 pmol/l;
b) urine
– premenopausal women – less than 450 µg / mmol creatinine,
– postmenopausal women – less than 800 µg / mmol creatinine,
– men – less than 450 µg / mmol creatinine.