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N-Telopeptide Cross-Links Blood Test

Last updated June 11, 2019

Approved by: Krish Tangella MD, MBA, FCAP

The N-Telopeptide Cross-Links Blood Test helps determine the levels of NTx in blood. It aids in the diagnosis of bone disorders such as osteoporosis.

What are other Names for this Test? (Equivalent Terms)

  • NTx Blood Test

What is N-Telopeptide Cross-Links Blood Test? (Background Information)

  • N-Telopeptide cross-links (NTx) are protein fragments created as a result of bone breakdown. NTx is used as a marker for bone degradation in disorders such as osteoporosis and osteopenia
  • Bone is made up of bone cells separated by bone matrix. About 90% of bone matrix is comprised of collagen, which has been cross-linked to make it stronger. The remaining components are inorganic salts such as bone mineral (hydroxyapatite)
  • Bone degradation causes the breakdown of these collagen fibers, which forms the telltale NTx fragments. The bone degradation is also carried out naturally by cells called osteoclasts. It occurs when calcium reserves are low, and as a normal part of bone maintenance and repair
  • Bone degradation is accelerated during conditions, such as osteoporosis and osteopenia, along with other bone disorders. NTx levels are significantly elevated in these cases
  • The N-Telopeptide Cross-Links Blood Test helps determine the levels of NTx in blood. It aids in the diagnosis of bone disorders such as osteoporosis

What are the Clinical Indications for performing the N-Telopeptide Cross-Links Blood Test?

Following are the clinical indications for performing the N-Telopeptide Cross-Links Blood Test:

  • Monitoring the effects of antiresorptive therapy
  • Frequent and/or unusual bone fractures
  • Loss of height
  • Hair loss
  • Brittle nails
  • Fatigue
  • Developmental issues, such as delayed onset of puberty

How is the Specimen Collected for N-Telopeptide Cross-Links Blood Test?

Following is the specimen collection process for N-Telopeptide Cross-Links Blood Test:

Sample required: Blood 

Process of obtaining a blood sample in adults:

  • A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
  • The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
  • The needle cap is removed and is held in line with the vein, pulling the skin tight
  • With a small and quick thrust, the vein is penetrated using the needle
  • The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
  • The wrap band is removed, gauze is placed on the collection site, and the needle is removed
  • The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
  • The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal

Preparation required: No special preparation is needed prior to the test.

What is the Significance of the N-Telopeptide Cross-Links Blood Test Result?

The following is the significance of the N-Telopeptide Cross-Links Blood Test:

  • A high value, greater than 19 nM BCE/L in women and 24.2 BCE/L in men, for the test may point to a diagnosis of the following conditions:
    • Osteoporosis
    • Osteopenia
    • Paget’s disease
    • Advanced bone tumors
    • Acromegaly
    • Hypoparathyroidism
    • Hypothyroidism 
  • A low value, less than 6.2 nM BCE/L in women and 5.4 BCE/L in men, for the test may point to a diagnosis of the following conditions:
    • Hypoparathyroidism
    • Hypothyroidism

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

The following DoveMed website link is a useful resource for additional information:


Please visit our Laboratory Procedures Center for more physician-approved health information:


References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Aug. 21, 2016
Last updated: June 11, 2019