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Test Code NTXPR NTX-Telopeptide, Urine

Reporting Name

NTX-Telopeptide, U

Useful For

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


Monitoring effectiveness of antiresorptive therapy in patients treated for osteopenia, osteoporosis, Paget disease, or other metabolic bone disorders

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Specimen Required

Patient Preparation: For 24 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.

Container/Tube: Plastic, 13-mL urine tube

Specimen Volume: 4 mL

Collection Instructions:

1. Collect second morning void.

2. No preservative.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 28 days
  Refrigerated  14 days
  Ambient  72 hours

Reference Values

All units are reported in nmol bone collagen equivalents (BCE)/mmol creatinine.



Tanner Stage I: 55-508 nmol BCE/mmol creatinine

Tanner Stage II: 21-423 nmol BCE/mmol creatinine

Tanner Stage III: 27-462 nmol BCE/mmol creatinine

Tanner Stage IV: <609 nmol BCE/mmol creatinine

Tanner Stage V: <240 nmol BCE/mmol creatinine



Tanner Stage I: 6-662 nmol BCE/mmol creatinine

Tanner Stage II: 193-514 nmol BCE/mmol creatinine

Tanner Stage III: 13-632 nmol BCE/mmol creatinine

Tanner Stage IV: <389 nmol BCE/mmol creatinine

Tanner Stage V: <132 nmol BCE/mmol creatinine


Adult (≥18 years of age)


21-83 nmol BCE/mmol creatinine



Premenopausal: 17-94 nmol BCE/mmol creatinine

Postmenopausal: 26-124 nmol BCE/mmol creatinine

Day(s) Performed

Monday, Thursday

Test Classification

This test has been cleared, approved, or is exempt by the US 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
NTXPR NTX-Telopeptide, U 44712-8


Result ID Test Result Name Result LOINC Value
NTXCT Creatinine, Random, U 2161-8
NTX NTX 27939-8
NTXCR NTX-Telopeptide, U 44712-8

Clinical Reference

1. Baxter I, Rogers A, Eastell R, Peel N: Evaluation of urinary N-telopeptide of type I collagen measurements in the management of osteoporosis in clinical practice. Osteoporos Int. 2013 Mar;24(3):941-947

2. Miller PD, Baran DT, Bilezikian JP, et al: Practical clinical application of biochemical markers of bone turnover: Consensus of an expert panel. J Clin Densitom. 1999;2(3):323-342

3. Delmas PD, Eastell R, Garnero P, Seibel MJ, Stepan J, Committee of Scientific Advisors of the International Osteoporosis Foundation: The use of biochemical markers of bone turnover in osteoporosis. Committee of Scientific Advisors of the International Osteoporosis Foundation. Osteoporos Int. 2000;11 Suppl 6:S2-S17

4. Mora S, Prinster C, Proverbio MC, et al: Urinary markers of bone turnover in healthy children and adolescents: age-related changes and effect of puberty. Calcif Tissue Int. 1998 Nov;63(5):369-374

Method Description

The Vitros N-terminal telopeptide (NTx) assay is a competitive immunoassay that depends on competition between NTx in the sample with a synthetic NTx peptide coated on the wells for binding by a horseradish peroxidase (HRP)-labeled antibody conjugate (mouse monoclonal anti-NTx). The conjugate is captured by the peptide coated on the wells, and unbound materials are removed by washing.


A reagent containing luminogenic substrates (a luminol derivative and a peracid salt) and an electron transfer agent (a substituted acetanilide) are added to the wells. The HRP in the bound conjugate catalyzes the oxidation of the luminol derivative, producing light. The electron transfer agent increases the level of light produced and prolongs the duration of light produced. The light signals are read by the system. The amount of HRP conjugate bound is inversely proportional to the concentration of NTx in the sample. Assay values are corrected for urinary dilution by urinary creatinine analysis and expressed in nanomoles bone collagen equivalents per liter (nM BCE/L) per millimole creatinine per liter (mM creatinine/L).(Instruction manual: Vitros Instructions for Use, N-Telopeptide GEM1426. Ortho-Clinical Diagnostics, Inc; Version 7.1, 09/06/2019)

Report Available

Same day/1 to 5 days

Reject Due To

Gross hemolysis Reject
Specimen with pH <5
Specimen containing preservatives

Method Name

NTXUR: Chemiluminescence Immunoassay

NTXCT: Enzymatic Colorimetric Assay

Secondary ID


Profile Information

Test ID Reporting Name Available Separately Always Performed
NTXCT Creatinine, Random, U No Yes
NTXUR NTX-Telopeptide, U No Yes