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C-Terminal Telopeptide of Type I Collagen (CTP) — Bone Turnover Marker

Published: August 9, 2026Updated: August 16, 2026

A bone turnover marker that measures collagen breakdown associated with bone resorption, helping assess skeletal turnover.

Quick summary

["C-telopeptide can help evaluate the rate at which bone is being broken down."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
24878-1
Short code
CT Petr part temp bone W contr IV
Synonyms
CT Petr part temp bone W contr IV
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

C-telopeptide, also called CTP, is a small fragment released when type I collagen is broken down. Because most type I collagen is found in bone, the test can help assess bone resorption, the process of breaking down bone.

Why might I need this test?

This test may be used to evaluate bone turnover in people with osteoporosis or other conditions that affect bone health. It may also help monitor treatment intended to slow bone loss.

How is the test performed?

C-telopeptide is generally measured in a blood sample, although urine testing may also be available. The laboratory uses a specialized assay to detect and quantify the collagen fragment.

How do I prepare for the test?

Follow the instructions provided with your order because preparation varies by specimen and laboratory. Some serum tests may require fasting, while a 24-hour urine collection requires collecting all urine for the specified period.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

C-Telopeptide (CTP)

Frequently asked questions

What does a high C-telopeptide result mean?
It may mean that bone is being broken down faster than usual. Your clinician will interpret the result alongside other bone health information.
Is C-telopeptide the same as a bone density test?
No. C-telopeptide measures bone turnover activity, while a bone density test estimates the amount and strength of bone.
Can this test diagnose osteoporosis by itself?
No. It can support bone health assessment, but osteoporosis is usually diagnosed using clinical information, risk factors, and often a bone density scan.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy