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23225 N-terminal Telopeptide, Serum (SNTX)

N-terminal Telopeptide, Serum (SNTX)
Test Code: NTXBSO
Synonyms/Keywords
Collagen Crosslinks; Crosslinked N-telopeptide of Type I Collagen (NTX), Serum; N-Telopeptide, Serum; NTX; Osteomark; Osteoporosis; N-Telopeptide X-Link, Serum  
Test Components
N-Terminal Telolpeptide
Useful For

Monitoring effectiveness of antiresorptive therapy in patients treated for osteoporosis or other metabolic bone disorders

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

This test is not useful for screening or diagnosing osteoporosis

Measurement of serum N-terminal telopeptide (NTx) is helpful for monitoring effectiveness of antiresorptive therapies in patients treated for osteoporosis or other metabolic bone disorders.

Specimen Requirements
 
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Serum​ ​Red Top Tube (RTT) ​Serum Separator Tube (SST) ​0.5 mL​0.1 mL
Collection Processing Instructions
Fasting is preferred due to diurnal variation of markers and food effects.  A morning collection from fasting patients is preferred. If not possible, collect the baseline and subsequent specimens under the same circumstances (eg, at same time of day).
 
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​Frozen (preferred) ​28 days
​Refrigerated ​24 hours
Rejection Criteria
Gross Hemolysis
​Gross Icterus
 Gross ​Lipemia
Interference

​Serum N-terminal telopeptide (NTx) 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.

Do not interchange the Osteomark NTx serum assay values with the Osteomark NTx urine assay values, especially when monitoring therapy.

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

Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available Methodology/Instrumentation
​Mayo Clinic Laboratories Sunday, Wednesday 2 to 5 days
Enzyme-Linked Immunosorbent Assay (ELISA)​
Reference Lab
Test Information

​Human bone is continuously remodeled through the process of bone formation and resorption. Measurement of bone turnover markers (BTM) in serum or urine serves as an indicator of bone formation or bone resorption cellular activities. BTM are physiologically elevated during childhood, growth, and during fracture healing. The elevations in bone resorption markers and bone formation markers are typically balanced in these circumstances and of no diagnostic value. Bone diseases occur when formation and resorption are uncoupled. In these situations, BTM might serve as predictors of therapy response. 

Telopeptides of type 1 collagen are the most extensively studied and used bone resorption markers. There are 2 forms depending on the cross-link forming site with collagen: the N-terminal telopeptide (NTx) and C-terminal telopeptide (CTx), which are released during collagen degradation.

In osteoporosis, a disease characterized by low bone mass and deterioration of bone tissue leading to increase skeletal fragility, measurement of BTM helps to determine treatment efficacy or patient's compliance with therapy. The advantage of measurement of BTM is that changes in response to therapy are observed within 3 to 6 months after therapy initiation; whereas changes in bone mineral density are not observed until 12 to 24 months posttherapy. Other diseases affecting the bone remodeling process, such as hyperthyroidism, all forms of hyperparathyroidism, most forms of osteomalacia and rickets (even if not associated with hyperparathyroidism), hypercalcemia of malignancy, Paget disease, multiple myeloma, bony metastases, as well as various congenital diseases of bone formation and remodeling, can result in accelerated and unbalanced bone turnover and elevation of BTM.

Reference Range Information
All units are reported in nmol Bone Collagen Equivalents (BCE)
Adult (> or =18 years of age)
Males: 5.4-24.2 nmol BCE
Females: Premenopausal: 6.2-19.0 nmol BCE
The target value for postmenopausal adult females undergoing treatment for osteoporosis is the same as the premenopausal reference interval.
Interpretation

​Elevated levels of N-terminal telopeptide (NTx) indicate increased bone resorption.

A 30% or greater reduction in this resorption marker 3 to 6 months after initiation of therapy indicates a probably adequate therapeutic response.

A common target of antiresorptive therapy in the treatment of postmenopausal osteoporosis is to achieve bone markers concentrations within the premenopausal reference range.

Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​82523
Synonyms/Keywords
Collagen Crosslinks; Crosslinked N-telopeptide of Type I Collagen (NTX), Serum; N-Telopeptide, Serum; NTX; Osteomark; Osteoporosis; N-Telopeptide X-Link, Serum  
Test Components
N-Terminal Telolpeptide
Ordering Applications
Ordering Application Description
​COM ​N-Telopeptide X-Link, Serum (SNTX)
​Cerner​N-terminal Telopeptide,Serum (SNTX)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
 
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Serum​ ​Red Top Tube (RTT) ​Serum Separator Tube (SST) ​0.5 mL​0.1 mL
Collection Processing
Fasting is preferred due to diurnal variation of markers and food effects.  A morning collection from fasting patients is preferred. If not possible, collect the baseline and subsequent specimens under the same circumstances (eg, at same time of day).
 
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​Frozen (preferred) ​28 days
​Refrigerated ​24 hours
Rejection Criteria
Gross Hemolysis
​Gross Icterus
 Gross ​Lipemia
Interference

​Serum N-terminal telopeptide (NTx) 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.

Do not interchange the Osteomark NTx serum assay values with the Osteomark NTx urine assay values, especially when monitoring therapy.

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

Useful For

Monitoring effectiveness of antiresorptive therapy in patients treated for osteoporosis or other metabolic bone disorders

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

This test is not useful for screening or diagnosing osteoporosis

Measurement of serum N-terminal telopeptide (NTx) is helpful for monitoring effectiveness of antiresorptive therapies in patients treated for osteoporosis or other metabolic bone disorders.

Test Components
N-Terminal Telolpeptide
Reference Range Information
All units are reported in nmol Bone Collagen Equivalents (BCE)
Adult (> or =18 years of age)
Males: 5.4-24.2 nmol BCE
Females: Premenopausal: 6.2-19.0 nmol BCE
The target value for postmenopausal adult females undergoing treatment for osteoporosis is the same as the premenopausal reference interval.
Interpretation

​Elevated levels of N-terminal telopeptide (NTx) indicate increased bone resorption.

A 30% or greater reduction in this resorption marker 3 to 6 months after initiation of therapy indicates a probably adequate therapeutic response.

A common target of antiresorptive therapy in the treatment of postmenopausal osteoporosis is to achieve bone markers concentrations within the premenopausal reference range.

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available Methodology/Instrumentation
​Mayo Clinic Laboratories Sunday, Wednesday 2 to 5 days
Enzyme-Linked Immunosorbent Assay (ELISA)​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​82523
For most current information refer to the Marshfield Laboratory online reference manual.