What is the Procollagen 1 Peptide N-Terminal (NTX) test?

The Procollagen 1 Peptide N-Terminal (NTX) test measures N-terminal telopeptides of type I collagen, which are released into the bloodstream when bone is broken down. NTX is a bone resorption marker, meaning it reflects how quickly bone tissue is being degraded.

Type I collagen is the main structural protein in bone. When bone resorption increases, NTX levels rise, providing a direct indicator of accelerated bone loss.

This test is commonly used alongside bone formation markers, calcium, vitamin D, and hormone tests to assess overall bone turnover and skeletal health.

Why do I need a test for NTX?

Bone loss often occurs silently before fractures develop. The NTX test helps identify increased bone breakdown early, allowing intervention before significant bone density loss occurs.

It is particularly useful in individuals at risk of osteoporosis, those undergoing hormone changes, or people receiving treatment that affects bone metabolism.

You may benefit from this test if you experience:

• Osteoporosis or osteopenia

• Recurrent or low-impact fractures

• Postmenopausal bone loss

• Long-term corticosteroid use

• Hormonal imbalance affecting bone health

• Monitoring response to osteoporosis treatment

• Chronic inflammatory or metabolic bone conditions

• Family history of bone disease

Benefits of the NTX test

1. Measures active bone breakdown
   Directly reflects bone resorption activity.

2. Supports osteoporosis risk assessment
   Identifies accelerated bone loss before fractures occur.

3. Monitors treatment effectiveness
   Helps assess response to osteoporosis therapies.

4. Provides dynamic bone health insight
   Shows ongoing bone turnover rather than static bone density.

5. Complements DEXA scanning
   Adds functional information alongside bone density imaging.

6. Useful in hormonal bone loss assessment
   Sensitive to postmenopausal and endocrine-related changes.

7. Supports fracture risk evaluation
   High NTX levels are associated with increased fracture risk.

8. Guides personalised bone health strategies
   Helps tailor lifestyle and clinical follow-up.

Step-by-step – how we offer NTX testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic

• Attend your appointment

• Blood sample collected by a qualified clinician or phlebotomist

• Sample is sent to the laboratory for analysis

At-home or hotel testing (+£60)

• A qualified phlebotomist visits your home or hotel

• Blood sample collected in a comfortable, familiar setting

• No clinic visit or travel required

Both services are available UK-wide.

Your NTX results explained

Low NTX levels

Low NTX levels indicate reduced bone resorption, suggesting stable or suppressed bone breakdown. This is often seen in individuals with effective osteoporosis treatment or balanced bone turnover.

Low levels are generally reassuring when interpreted alongside bone formation markers.

UK reference interpretation:

• Low: Below laboratory reference range

Normal NTX levels

Normal NTX levels suggest balanced bone resorption appropriate for age and physiological status. This indicates stable skeletal turnover.

Results should be assessed together with bone density and clinical risk factors.

UK reference interpretation:

• Normal: Within laboratory reference range

High NTX levels

High NTX levels indicate increased bone breakdown and accelerated bone loss. This may occur in osteoporosis, postmenopausal bone loss, hyperparathyroidism, or untreated metabolic bone disease.

Elevated levels are associated with increased fracture risk.

UK reference interpretation:

• High: Above laboratory reference range