Test Overview

Test Methodology


Test Usage

This test is used for monitoring effectiveness of antiresorptive therapy in patients treated for osteoporosis or other metabolic bone disorders or as an adjunct in the diagnosis of medical conditions associated with increased bone turnover.

Reference Range*

All units are reported in nmol Bone Collagen Equivalents (BCE). Adult Male: 5.4-24.2 nmol BCE; Adult Female, Premenopausal: 6.2-19.0 nmol BCE.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

Some patients who have been exposed to animal antigens, either in the environment or as part of treatment or imaging procedures, may have circulating antianimal antibodies present. These antibodies may interfere with the assay reagents to produce unreliable results.

Test Details

Days Test Performed

Tuesday, Thursday

Analytic Time

2 - 6 days

Soft Order Code


MiChart Code

NTx Serum (Sendout)



N-Telopeptides, Serum
Pyrrolinks-D, Serum
Crosslinked N-telopeptide of Type 1 Collagen, Serum
Type I Collagen (NTX), Serum
Collagen Crosslinks, Serum
N-Telopeptide, Cross-Linked, Serum

+ See More



Laboratory Reference


Looking to Order a Test?

We’ve provided helpful links to make ordering easy.

Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

Visit our provider FAQ and learn about common questions to ordering tests.

Specimen Requirements

Offsite Collection Instructions

Collect specimen in a red top or SST tube from a fasting patient (preferred). Centrifuge, aliquot serum into a plastic vial and freeze.


This test should not be used for the screening or diagnosis of osteoporosis. In patients with other clinical conditions known to affect bone resorption (eg; cancer metastases to bone), interpretation of serum NTx for monitoring response to osteoporosis therapy might be unreliable.

Fasting Specimen

A morning collection from fasting patients is preferred. If not possible, collect the baseline and subsequent specimens under the same circumstances (e.g., at same time of day).


Yellow Top Tube

Normal Volume

0.5 mL serum

Minimum Volume

0.1 mL serum

Additional Information

Test sent to Mayo Medical Laboratories.

Billing Information

Fee Codes

CPT Code


Have More Billing Questions?

Explore our helpful billing resources:

Billing Resources

Billing FAQ