test directorySearch Results
Click here to search again.
Test Name:
Beta-C-Terminal Telopeptide, Serum or Plasma
- SBMF No:
23340 - Performance Lab Name:
Automated Lab - Test Mnemonic:
BETA CTX - ABN:
May be required – Medical Necessity - CPT Code:
82523 - LOINC Code:
41171-0 - Also Known As:
β-Carboxyl-Terminal Cross-Linking Telopeptide of Type I Collagen
β-CrossLaps
β-CTx
Carboxyl-Terminal Cross-Linking Telopeptide of Type I Collagen
CrossLaps
C-Terminal Telopeptide
CTx - Spec Type:
Serum - Spec Container:
Gold top (SST) or red top (serum) tube - Alt Spec Type:
Plasma - Alt Spec Container:
Lavender top (EDTA) tube - Pref Vol:
0.5 mL - Min Vol:
0.3 mL - Fasting:
Yes - Patient Prep:
Fasting morning sample recommended since CTx is influenced by food intake and circadian rhythm - Spec Collect:
Due to bone marker diurnal variation, consistent collection conditions recommended for long-term monitoring
Routine venipuncture - Spec Process:
Serum sample tubes, clot 30 minutes
Promptly centrifuge 15 minutes
Immediately transfer serum or plasma to 13 x 100 plastic transfer tube and freeze - Spec Store Transport:
Frozen - Spec Stability:
- Serum:
- – 8 hours room temperature (20-30°C)
– 8 hours refrigerated (2-8°C)
– 3 months frozen (-20°C)
EDTA plasma:- – 24 hours room temperature (20-30°C)
– 8 days refrigerated (2-8°C)
– 3 months frozen (-20°C)
- Methodology:
Electrochemiluminescent Immunoassay (ECLIA) - Use:
Monitor bone resorption - Clinical Significance:
CTx and NTx are crosslinked telopeptides of type I collagen that are derived from C-terminal and N-terminal, respectively. Both are efficient markers for bone resorption and have been found to correlate significantly with bone mineral density (BMD) change in the distal third of the radius. These markers differed significantly for groups of patients with fast and slow bone loss while other bone markers did not. This suggests that they are the better markers for assessing the bone metabolic state and thus are the better predictors for the rate of bone loss or fracture risk.
The β-C-terminal telopeptide (β-CTx) assay is specific for crosslinked isomerized type I collagen fragments and quantifies all type I collagens. The beta-form is an isomer of C-terminal telopeptide (CTx). β-CTx, a newer bone marker, has been shown to correlate well with NTx by several studies including an in-house study conducted at SBMF. However, in its favor, β-CTx can be performed at a significantly lower cost than NTx.
EDTA plasma, or serum, is the sample of choice for testing, rather than a 24-hour urine collection. This judgment is derived not only from the ease of specimen collection and processing, but also from the observation that there is less variation in plasma and serum markers than in urine markers.
- Reference Range:
Male: up to 0.608 ng/mL
Female: up to 0.534 ng/mL - Day Run:
Mon, Wed, Fri - Time Run:
2:00 pm - Time Reported:
Within 24 hours - Test Type:
CHEMISTRY
