Test Code

Quest Code

CPT Codes

Preferred Specimen
1 mL serum

Patient Preparation
A minimum of 12 hours fasting is required. Fasting morning collection 8-10 am. (Diurnal variations cause elevated levels at night.)

Dietary supplements containing biotin may interfere in assays and may skew results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation.

Minimum Volume
0.5 mL

Allow blood to clot (10-15 minutes) at room temperature. Centrifuge and separate the serum from the cells. Freeze as soon as possible.

Transport Container
Plastic screw-cap vial

Transport Temperature

Specimen Stability
Room temperature: 1 day
Refrigerated: 14 days
Frozen: 2 years

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Moderate to gross hemolysis • Grossly lipemic • Grossly icteric

Immunoassay (IA)

Setup Schedule

Report Available
3 to 6 Day(s)

Reference Range
Adult Male  
18-29 Years 87-1200 pg/mL
30-39 Years 70-780 pg/mL
40-49 Years 60-700 pg/mL
50-68 Years 87-345 pg/mL
Adult Female  
18-29 Years 60-640 pg/mL
30-39 Years 60-650 pg/mL
40-49 Years 40-465 pg/mL
>49 Years Not established
Pediatric Male  
5-9 Years 574-1849 pg/mL
10-13 Years 519-2415 pg/mL
14-17 Years 435-2924 pg/mL
Pediatric Female  
5-9 Years 574-1849 pg/mL
10-13 Years 519-2415 pg/mL
14-17 Years 242-1291 pg/mL

Clinical Significance

CTx is useful to assess bone resorption in patients with metabolic bone disease. The test is also useful in monitoring therapy to slow or halt osteoporotic bone loss.

Performing Laboratory
Quest Diagnostics Nichols Institute San Juan Capistrano
33608 Ortega Hwy
San Juan Capistrano, CA 92675-2042

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.