Cerebrotendinous Xanthomatosis, Blood
Use
This test is useful for evaluating patients who have a clinical suspicion of cerebrotendinous xanthomatosis (CTX) and for monitoring individuals with CTX who are on chenodeoxycholic acid (CDCA) therapy. It is an essential test for early diagnosis as it helps prevent the progression of CTX, a disorder caused by the deficiency of the mitochondrial enzyme sterol 27-hydrolase, leading to the accumulation of cholestenol and ketosterol bile acid precursors in body tissues.
Special Instructions
This test should not be used for identifying carriers or assessing bile acid malabsorption in patients with irritable bowel syndrome-diarrhea. For the latter, the 7AC4 Bile Acid Synthesis test in serum should be ordered. If this test is ordered along with GPSYW or OXYWB, they will be canceled, and HSMWB will be ordered instead.
Limitations
The test is not useful for the identification of carriers or for evaluating bile acid malabsorption. Conditions such as bile acid malabsorption or ileal resection may cause elevated levels of 7-alpha-hydroxy-4-cholesten-3-one (7aC4), potentially leading to diagnostic confusion. Appropriate specimen collection and handling are critical as improper procedures may affect the results.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 92737-6
- 59462-2
- 92762-4
- 92759-0
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
1 mL
Minimum Volume
0.25 mL
Container
Lavender top (EDTA)
Collection Instructions
Send whole blood in original vial. Do not aliquot.
Causes for Rejection
Gross hemolysis: OK; Gross lipemia: OK; Gross icterus: OK
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 72 hours |