N-Telopeptide, Cross-Linked, Urine
Use
The N-Telopeptide, Cross-Linked, Urine test is used primarily for monitoring bone resorption in conditions such as osteoporosis. A decrease in NTx levels by 30-40% from baseline after three months of anti-resorptive therapy is considered a typical therapeutic response. This test measures the cross-linked N-telopeptide of type I collagen, which is released during bone resorption.
Special Instructions
For effective monitoring of therapy, it's essential to collect a baseline specimen prior to initiation of treatment. Subsequent samples should be collected at the same time of day as the baseline for comparison. The complete set of age and gender-specific reference intervals can be accessed in the ARUP Laboratory Test Directory.
Limitations
NTx levels can be influenced by various factors, including circadian rhythm and dietary changes, which might affect the test results. Therefore, it's recommended to collect subsequent specimens at the same time of day for consistency. Samples contaminated with blood or showing extensive hemolysis are not acceptable for testing.
New York Approved
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 14115-0
- 35674-1
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
1 mL
Minimum Volume
0.5 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Collect second-morning void or 24-hour urine without preservative.
Patient Preparation
For monitoring therapy, collect a baseline specimen prior to initiation of therapy. Collect subsequent specimens at the same time of day.
Storage Instructions
Frozen.
Causes for Rejection
Specimens contaminated with blood or extensive hemolysis.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 1 week |
| Frozen | 4 weeks |