Pathology Handbook

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C-Telopeptide

Alternative Names:

CTX

Laboratory:

Clinical Biochemistry

Test Code:

CTX

Specimen Types:

Plasma

Container Types:

EDTA 6 mL
SST

Collection & Request Instructions:

Collect in am
Fasting Sample

Marker of bone resorption. Useful for monitoring the effect of anti-resorptive therapy and patient compliance.

Plasma EDTA is the preferred sample as it is stable longer than serum.

Stability of K2- and K3-EDTA plasma: 24 hrs at 20-25C, 8 days at 2-8C

3 months at -20C. For longer periods store at -70C. Freeze only ONCE.

Serum is only stable 6 hrs at 20-25 C, 8 hrs at 4 - 8C, 3 months at -20C. For longer periods store at -70C. Freeze only ONCE

Haemolyzed samples (Hb> 0.5 g/dL) elicit a decrease in the C-Telopeptide (Beta- crosslaps) concentration.

Transport Instructions between Sites and/or Laboratories:

Send to lab immediately
Use Esky from SDMH or CGMC to Alfred

For external sites transport to Alfred Pathology Frozen.

Assay Frequency:

Weekdays

Additional Notes:

Reference Intervals:

CTX – C-Telopeptide – Serum carboxy-terminal cross-linking telopeptide of type 1 collagen

Female:

Age	Reference intervals: ng/L
6 months – < 6 yrs	450 – 1800
6 – <11 yrs	820 - 2010
11 – <15 yrs	490 - 2760
15 - <16yrs	120-1730
16 – <20 yrs	120 - 1590
20 – <50yrs* *This reference interval applies to pre-menopausal women, values can be higher in < 40 y.o.	150 – 800
50 – <70yrs * *This reference interval applies to post- menopausal women.	50 – 800
≥ 70 yrs	100 – 1000

Male:

Age	Reference intervals: ng/L
6 months – < 6 yrs	450 – 1800
6 – <10 yrs	1050 - 2380
10 – <16 yrs	1000 - 2900
16 - <20 yrs	500 - 2430
20 – <25 yrs* *Please note values can be higher before growth plate closure.	400 – 900
25 – <70 yrs	100 – 600
≥ 70 yrs	100 – 750

Reference Interval Sources:

1) Wyness S et al. Clinica Chimica Acta 2013; 169-172.

2) Vasikaran S, Chubb P, Schneider HG. Towards optimising the provision of laboratory services for bone turnover markers. Pathology 2014; 46(4):267-273.

Note: Higher levels may be seen in women < 40 yrs.

Note: Reference Intervals above amended to include age related intervals for children from 28/09/2015.

Assay performed on Roche cobas e801 (ECLIA)

Note: Biotin supplementation may cause falsely low results due to interference with the C-Telopeptide assay. If the patient is known to be taking Biotin, interpret results with caution and contact the Chemical Pathologist (03) 90763118 if further discussion is required.