What is the Procollagen III Peptide test?

The Procollagen III Peptide (PIIINP) blood test measures fragments released during the formation of type III collagen, a key structural protein found in skin, blood vessels, lungs, liver, and other soft tissues.

When new collagen is produced, PIIINP is released into the bloodstream, making it a marker of connective tissue synthesis and turnover. Elevated levels reflect increased tissue repair, inflammation, or fibrotic activity.

This test is commonly used to assess fibrotic processes and connective tissue activity in conditions affecting the liver, lungs, heart, and systemic inflammatory states.

Why do I need a test for Procollagen III Peptide?

Excessive collagen production can lead to fibrosis, where normal tissue is replaced by stiff, scar-like tissue. The Procollagen III Peptide test helps identify increased fibrotic or inflammatory activity before irreversible tissue damage occurs.

It is particularly useful when investigating unexplained organ dysfunction, monitoring fibrotic disease activity, or assessing tissue repair following injury or inflammation.

You may benefit from this test if you experience:

• Chronic liver disease or suspected liver fibrosis

• Lung conditions with fibrotic involvement

• Heart or vascular disease with connective tissue changes

• Systemic inflammatory or autoimmune disorders

• Unexplained organ stiffness or reduced function

• Monitoring progression of fibrotic conditions

• Evaluation of tissue repair or scarring processes

• Chronic inflammatory states

Benefits of the Procollagen III Peptide test

1. Assesses connective tissue turnover
   Reflects active collagen synthesis in soft tissues.

2. Supports fibrosis assessment
   Helps identify early or ongoing fibrotic processes.

3. Useful in liver disease evaluation
   Elevated levels may reflect hepatic fibrosis activity.

4. Relevant for lung and vascular conditions
   Type III collagen is abundant in pulmonary and vascular tissue.

5. Monitors inflammatory tissue repair
   Indicates active healing or scarring responses.

6. Supports chronic disease monitoring
   Useful in long-term inflammatory or fibrotic disorders.

7. Non-invasive fibrosis marker
   Requires only a blood sample.

8. Guides further clinical investigation
   Helps determine need for imaging or specialist referral.

Step-by-step – how we offer Procollagen III Peptide 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 Procollagen III Peptide results explained

Low PIIINP levels

Low levels indicate minimal connective tissue synthesis and low fibrotic activity. This suggests stable tissue turnover without excessive scarring or inflammation.

Low results are generally reassuring when symptoms are mild or absent.

UK reference interpretation:

• Low: Below laboratory reference range

Normal PIIINP levels

Normal levels suggest balanced collagen production and healthy connective tissue turnover. This indicates appropriate tissue maintenance and repair activity.

Results should always be interpreted alongside clinical findings.

UK reference interpretation:

• Normal: Within laboratory reference range

High PIIINP levels

High levels indicate increased collagen synthesis, often associated with fibrosis, chronic inflammation, or active tissue repair. Persistently elevated results may suggest progressive fibrotic disease.

Further investigation may be advised depending on symptoms and associated markers.

UK reference interpretation:

• High: Above laboratory reference range