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Test ID: CTX Beta-CrossLaps, Serum

Reporting Name

Beta-CrossLaps (B-CTx), S

Useful For

Monitoring antiresorptive therapies (eg, bisphosphonates and hormone replacement therapy) in postmenopausal women treated for osteoporosis and individuals diagnosed with osteopenia

 

An adjunct in the diagnosis of medical conditions associated with increased bone turnover

Clinical Information

Human bone is continuously remodeled through a process of bone formation and resorption. Approximately 90% of the organic matrix of bone is type I collagen, a helical protein that is crosslinked at the N- and C-terminal ends of the molecule. During bone resorption, osteoclasts secrete a mixture of acid and neutral proteases that degrade the collagen fibrils into molecular fragments including C-terminal telopeptide (CTx). As bone ages, the alpha form of aspartic acid present in CTx converts to the beta form. Beta-CTx is released into the bloodstream during bone resorption and serves as a specific marker for the degradation of mature type I collagen. Elevated serum concentrations of beta-CTx have been reported in patients with increased bone resorption.

 

Bone turnover markers are physiologically elevated during childhood, growth, and fracture healing. The elevations in bone resorption markers and bone formation markers are typically balanced in these circumstances and are of no diagnostic value. By contrast, bone turnover markers may be useful when the bone remodeling process is unbalanced. Abnormalities in the process of bone remodeling can result in changes in skeletal mass and shape. Many diseases, in particular hyperthyroidism, all forms of hyperparathyroidism, most forms of osteomalacia and rickets (even if not associated with hyperparathyroidism), hypercalcemia of malignancy, Paget disease, multiple myeloma, and bone metastases, as well as various congenital diseases of bone formation and remodeling, can result in accelerated and unbalanced bone turnover. Unbalanced bone turnover is also found in age-related and postmenopausal osteopenia and osteoporosis.

 

Disease-associated bone turnover abnormalities should normalize in response to effective therapeutic interventions, which can be monitored by measurement of serum and urine bone resorption markers.

Interpretation

Elevated levels of beta-C-terminal telopeptide (CTx) indicate increased bone resorption. Increased levels are associated with osteoporosis, osteopenia, Paget disease, hyperthyroidism, and hyperparathyroidism.

 

In patients taking antiresorptive agents (bisphosphonates or hormone replacement therapy), a decrease of 25% or more from baseline beta-CTx levels (ie, prior to the start of therapy) 3 to 6 months after initiation of therapy indicates an adequate therapeutic response.

Analytic Time

Same day/1 day

Day(s) and Time(s) Performed

Monday through Friday; 5 a.m.-12 a.m.

Saturday; 6 a.m.-6 p.m.

Clinical Reference

1. Christgau S, Bitsch-Jensen O, Hanover Bjarnason N, et al: Serum CrossLaps for monitoring the response in individuals undergoing antiresorptive therapy. Bone. 2000 May;26(5):505-511

2. Garnero P, Borel O, Delmas PD: Evaluation of a fully automated serum assay for C-terminal cross-linking telopeptide of type I collagen in osteoporosis. Clin Chem. 2001 Apr;47(4):694-702

3. Fraser W: Bone and Mineral Metabolism. In Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier;2018;1422-1491

4. Delmas PD, Eastell R, Garnero P, et al: The use of biochemical markers of bone turnover in osteoporosis. Committee of Scientific Advisors of the International Osteoporosis Foundation. Osteoporo Int. 2000;11:S2-S17

Method Name

Electrochemiluminescence Immunoassay (ECLIA)

Specimen Type

Serum


Specimen Required


Patient Preparation:

1. For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

2. Patient should be fasting.

Supplies: Aliquot Tube, 5 mL (T465)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial, 5 mL

Specimen Volume: 1 mL

Collection Instructions:

1. Collect specimen prior to 10 a.m.

2. Centrifuge and aliquot serum into plastic vial.


Specimen Minimum Volume

0.75 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 90 days
  Refrigerated  72 hours

Reference Values

Males

<5 years: 242-1292 pg/mL

5-9 years: 351-1532 pg/mL

10-15 years: 447-2457 pg/mL

16-17 years: 478-1666 pg/mL

18-30 years: 120-946 pg/mL

31-50 years: 93-630 pg/mL

51-70 years: 35-836 pg/mL

>70 years: not established

 

Females

<5 years: 347-1508 pg/mL

5-9 years: 383-1556 pg/mL

10-15 years: 311-1776 pg/mL

16-17 years: 146-1266 pg/mL

Premenopausal: 25-573 pg/mL

Postmenopausal: 104-1008 pg/mL

Test Classification

This test has been cleared, approved or is exempt by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

82523

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CTX Beta-CrossLaps (B-CTx), S 41171-0

 

Result ID Test Result Name Result LOINC Value
CTX Beta-CrossLaps (B-CTx), S 41171-0
Mayo Clinic Laboratories | Endocrinology Catalog Additional Information:

mml-bone-minerals