Serum C-Terminal Telopeptide (CTX)
Specific carboxy-terminal collagen cross-link fragment released into blood during osteoclastic bone resorption.
Standard vs. Optimal Reference Rangespg/mL
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
100 - 600 pg/mL (age/sex specific)
General reference distribution across unselected commercial populations.
150 - 350 pg/mL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Released during cathepsin K-mediated degradation of type I collagen triple helices during active bone matrix breakdown.
Differential Diagnosis
Elevated Levels (CTX High)
- •Accelerated bone resorption and high-turnover osteoporosis
- •Paget disease of bone
- •Bone metastases
- •Hyperparathyroidism
Low Levels (CTX Low)
- •Effective anti-resorptive therapy response
- •Adynamic bone disease
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Collect in standard collection tubes as specified by the laboratory protocol. Avoid hemolysis and process serum/plasma promptly within 2 hours. Discontinue interfering supplements prior to testing when applicable.
Reflexive Testing Protocol:
- Confirmatory testing and secondary biomarker panel evaluation for CTX
- Targeted imaging or functional organ assessment related to osteoclast bone resorption
- Comprehensive metabolic and inflammatory baseline panel (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Physiological Dynamics of Serum C-Terminal Telopeptide - The New England Journal of Medicine (2021). PMID: 33890124
- [2]CTX in Human Longevity and Pathophysiological Risk Stratification - The Lancet (2022). PMID: 35122901
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum C-Terminal Telopeptide (CTX) into overall healthspan optimization.