FISH Study: Prenatal Metaphase Microdeletion

Additional Information:

UFHPL Test #: 30270

CPT Code(s):

  • 88271
  • 88275
  • 88291

Collection Procedure:


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.

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

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 older than 48 hours upon receipt. Refrigeration at 2° - 8° C may assist when a delay is not preventable. Do not freeze or place specimens directly on ice.


This test is used to detect the presence of a specific fetal microdeletion for any of the microdeletion syndromes for which testing is available by our laboratory. Orders should include a relevant family history and or specific ultrasound findings.


Metaphase microdeletion fluorescence in-situ hybridization (FISH) analysis for specific conditions; requires concurrent classic cytogenetic analysis; not for standalone use


10 - 14 days

Reference Values:

By report; interpretive


Monday - Saturday

Interpretation Data: