FISH Study: Prenatal X/Y

Interphase nuclei fluorescence in-situ hybridization (FISH) analysis for sex chromosome constitution; requires concurrent classic cytogenetic analysis; not for standalone use
Monday - Saturday
2 - 4 days

This screening test is only used to detect fetal sex in cases with an established history of sex-linked disorders.

Specimen Requirements: 
  • Amniotic Fluid: Aseptically collect approximately 1 cc of per week of gestational age in two sterile 15 mL conical centrifuge tubes and sequentially label the tubes. The initial 1 - 2 cc should not be included for chromosome studies (but may be utilized for AFP testing).
  • Chorionic Villi: Collect 10 - 30 mg of utilizing aspiration medium containing sodium heparin.* After assessment of the appropriate amount and quality of villi, transfer to a sterile centrifuge tube with transportation medium.

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.

Contact UF Health Pathology Laboratories prior to submission (approved by consultation).

Reference Values: 

By report; interpretive

CPT Code (s): 
  • 88271 x 2
  • 88274
  • 88291

UFHPL Test #: 30275

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