FISH Study: Prenatal X/Y

Additional Information:

UFHPL Test #: 30275

CPT Code(s):

  • 88271 x 2
  • 88274
  • 88291

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).


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


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


2 - 4 days

Reference Values:

By report; interpretive


Monday - Saturday