ARUP's Laboratory Test Directory

0070062: N-Telopeptide, Cross-Linked, Urine

Test Mnemonic: NTX
Methodology: Chemiluminescent Immunoassay

Performed: Tue-Sat

Reported: 1-4 days

Specimen Required:  
Collect: Second-morning void or 24-hour urine. Specimen must be refrigerated during collection. Collect without preservative.

Transport: 1 mL aliquot from a well-mixed, second-morning void or 24-hour collection, frozen. (Min: 0.5 mL)  Submit specimen in an ARUP Standard Transport Tube.

Pediatric Collection/Transport: 0.5 mL aliquot from a well-mixed, second-morning void or 24-hour collection, frozen.

Remarks: For monitoring therapy, a baseline specimen should be collected prior to initiation of therapy. Subsequent specimens for comparison should be collected at the same time of day as the baseline specimen.

Unacceptable Conditions: Specimens contaminated with blood or with extensive hemolysis.

Stability: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 2 years

Reference Interval:
 
Age Male Female
7-9 years 167-578 nM BCE/mM creatinine 201-626 nM BCE/mM creatinine
10-12 years 152-505 nM BCE/mM creatinine 173-728 nM BCE/mM creatinine
13-15 years 103-776 nM BCE/mM creatinine 38-515 nM BCE/mM creatinine
16-17 years 34-313 nM BCE/mM creatinine 20-144 nM BCE/mM creatinine
18 years and older 21-83 nM BCE/mM creatinine  
Premenopausal  17-94 nM BCE/mM creatinine
Postmenopausal  26-124 nM BCE/mM creatinine

Interpretive Data:
NTx Units = nM BCE/mM creatinine

A decrease of 30-40% from the NTx baseline after three months of therapy is a typical response to anti-resorptive therapy.

NTx = Cross-linked N-telopeptide of Type I Collagen
BCE = Bone Collagen Equivalent



CPT Code(s):
82523

 

 

 
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