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Test Code BCTX 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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


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


<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



<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

Day(s) and Time(s) Performed

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

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

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


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

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 Description

The Roche Beta-CrossLaps assay is a 2-site immunometric (sandwich) assay using electrochemiluminescence detection. Patient specimen, biotinylated monoclonal beta-CrossLaps-specific antibody, and monoclonal beta-CrossLaps-specific antibody labeled with ruthenium react to form a complex. Streptavidin-coated microparticles act as the solid phase to which the complex binds. Voltage is applied to the electrode, inducing a chemiluminescent emission from the ruthenium, which is then measured against a calibration curve to determine the amount of beta-CrossLaps in the patient specimen. This assay is specific for crosslinked isomerized type I collagen fragments, independent of the nature of the crosslink (eg, pyrrole, pyridinolines). The assay specificity is guaranteed through the use of 2 monoclonal antibodies, each recognizing linear beta-8AA octapeptides (EKAHD-beta-GGR). The assay, therefore, quantifies all type I collagen degradation fragments that contain the isomerized octapeptide beta-8AA twice (beta-CTx).(Package insert: Elecsys Beta-CrossLaps/serum. Roche Diagnostics; V1.0, 05/2017)

Analytic Time

Same day/1 day

Reject Due To

Gross hemolysis Reject
Gross lipemia OK

Method Name

Electrochemiluminescence Immunoassay (ECLIA)

Secondary ID