Known 45,X, Mosaicism Reflex Analysis, FISH, Whole Blood
Use
This test is used for detecting sex chromosome mosaicism in patients with a 45,X karyotype. It is particularly helpful in identifying mosaicism in patients diagnosed with Ullrich-Turner syndrome (UTS), a genetic disorder characterized by the apparent loss of a sex chromosome. The test provides valuable information for the clinical management of patients, as those with a Y chromosome have an increased risk of gonadoblastoma. Accurate identification of mosaicism is crucial for understanding phenotypic expression and providing appropriate clinical management.
Special Instructions
A reason for testing is required, although testing will not be rejected if not provided; however, an appropriate indication may be entered by Mayo Clinic Laboratories. Specimen shipping should use Express Mail or equivalent if not using a courier service. New York clients must obtain informed consent for genetic testing, which must be documented on the order form or electronic order.
Limitations
This test does not detect other chromosomal or structural anomalies and should be ordered after a complete chromosome analysis. It is not approved by the US Food and Drug Administration and should be used as an adjunct to confirm an X or Y chromosome mosaicism diagnosis, alongside existing clinical history or physical evaluation. Interfering factors include cell lysis from rapid needle blood draw, improper anticoagulant use, excessive transport time, and exposure to temperature extremes, leading to potential cell death and analytical interference.
New York Approved
Methodology
Chromosomal / Cytogenetics (FISH)
Biomarkers
LOINC Codes
- 87436-2
- 50397-9
- 69965-2
- 62356-1
- 42349-1
- 31208-2
- 85069-3
Result Turnaround Time
7-9 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
4 mL
Minimum Volume
2 mL
Container
Green top (sodium heparin) preferred; Lavender top (EDTA) or yellow top (ACD) acceptable
Collection Instructions
Invert several times to mix blood. Send whole blood specimen in original tube. Do not aliquot. Other anticoagulants are not recommended and are harmful to the viability of the cells. Cord blood is acceptable.
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability. Specimen cannot be frozen.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Ambient (preferred) |
| Refrigerated | Refrigerated |