FISH for 22q11.2 Del, VCF, DiGeorge




Test Mnemonic

DGEORG

CPT Codes

  • 88271 - QTY (2)
  • 88275 - QTY (1)

Aliases

  • Catch 22 Syndrome
  • FISH for DiGeorge Syndrome
  • FISH for VCF
  • Shprintzen Syndrome
  • VCFS
  • Velocardiofacial Syndrome

Performing Laboratory

Mayo Clinic Dpt of Lab Med & Pathology


Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
5 mLWhole bloodSodium heparin (Green) AmbientProvide reason for referral with specimen.

Alternate Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
30 mgChorionic VillusTransport Medium Refrigerated 
4 mmBiopsy, skinSterile container RefrigeratedUse Hank's balanced salt solution, Ringer's solution or normal saline in container. Do not handle specimen with hands.
20 - 25 mLFluid, amnioticSterile container RefrigeratedCollect specimen in sterile syringe, discard first 2 mL and send remainder in sterile container. Collect during 14 - 18 weeks gestation. Provide gestational age at time of amniocentesis and reason for referral with specimen.

Minimum Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
2 mL     

Stability

Environmental Condition Description
AmbientWhole blood: 96 hours
RefrigeratedWhole blood: 96 hours
FrozenUnacceptable

Days Performed

Sun - Sat

Turnaround Time

3 - 8 days

Methodology

Name Description
Fluorescent In-Situ Hybridization (FISH) 

Reference Range

Special Info

Patients residing in New York State must sign an informed consent form. TESTING ALGORITHM: This test only includes a charge for professional interpretation of results and does not include charges for probe application or anlysis. Charges will be incurred for application of all probes applied. Analysis charges will be incurred based on the number of cells analyzed per probe set. If no cell are available for analysis, no analysis charges will be incurred.

Clinical Info

Useful for the detection of a submicroscopic deletion that has been associated with DGS, VCFS, and CATCH 22. Also may be useful to detect cryptic translocation involving 22q11.2. Any individual with a normal signal pattern in each metaphase is considered negative for this probe. This may be due to microdeletions outside the region tested by this probe, or point mutations or small deletions within the hybridization region.