FISH Study: X/Y Interphase (Sex Chromosome Constitution)

Methodology: 
Metaphase and/or chromosome fluorescence in-situ hybridization (FISH) analyses; requires cell culture and a concurrent or previous routine karyotyping
Performed: 
Monday - Saturday
Reported: 
10 - 28 days
Use: 

This test is used to assist in determining sex chromosome constitution in patients suspected to have conditions in which mosaicism is likely (i.e., ambiguous genitalia, Turner syndrome, etc.).

Specimen Requirements: 
  • Peripheral Blood: Collect blood aseptically in sodium heparin tubes (usually green-top tubes) and immediately rotate thoroughly to prevent clotting. For infants, obtain approximately 2 cc, and for children and adults, obtain 5 - 7 cc.
  • Skin biopsy or Other Tissues: In an aseptic manner, obtain approximately 2 mm x 2 mm, which is deep enough to ensure that the dermal layer is included. Deposit the specimen in a sterile container containing tissue culture medium with antibiotics which has been brought to room temperature prior to collection.* Alternate solid tissue samples include autopsy specimens (i.e., lung, cartilage, etc.).

Note: A separate blood sample is required if a concurrent CGH microarray study is desired.

Do not freeze or fix samples in any manner contrary to the maintenance of cell viability. Maintain sample sterility; keep all specimens at room temperature; and deliver samples to the laboratory within 24 - 48 hours. Ship specimens at room temperature for overnight delivery.

  • Unacceptable Conditions:
    • Frozen specimens
    • Specimens greater than 48 hours old*
  • Stability (collection to initiation of testing):
    • Ambient: 24 - 48 hours*
    • Frozen: Unacceptable

* Cell viability of specimens requiring cell culture may be compromised in specimens more than 48 hours old upon receipt. Refrigeration at 2° - 8° C may assist when a delay is not preventable. Do not freeze or place specimens directly on ice.

Reference Values: 

By report; interpretive

CPT Code (s): 
  • 88271x 2
  • 88273
  • 88275
  • 88291
Notes: 

UFHPL Test #: 30285

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