FISH Study: Prenatal Chromosome Identification

CPT Code(s):

  • 88271
  • 88273
  • 88291


Metaphase fluorescence in-situ hybridization analysis (FISH) for characterization of de novo chromosomal findings; requires concurrent classic cytogenetic analysis; not for standalone use


Monday - Saturday


10 - 21 days


This test is used further characterize chromosome abnormalities as previously identified by conventional G-banding techniques in prenatal studies (e.g., marker chromosome identification, derivative chromosome content, breakpoint analysis, etc.).

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).

Collection Procedure:


Reference Values:

By report; interpretive

Interpretation Data:



UFHPL Test #: 30265

Reported Notes: