DiGeorge/VCF: (22q11.2) FISH Analysis

FISH analysis for DiGeorge/Velocardiofacial (VCF) syndrome is a cytogenetic test used to identify deletions or duplications in chromosome region 22q11.2. FISH is also utilized to confirm microdeletions identified during high resolution chromosome analysis.

Turnaround Time

4 weeks

CPT Code(s)

88275, 88273, 88271, 88291

Cost

$584

Chromosomes

• DiGeorge also velocardial facial (VCF)

Fluorescence in situ hybridization is a molecular cytogenetic technique in which fluorescently labeled DNA probes are hybridized to metaphase spreads or interphase nuclei. Applications include identification of structurally abnormal chromosomes, including identification of marker chromosomes, detection of very small deletions (microdeletions), and rapid detection of Down syndrome and other numerical chromosome abnormalities; and the rapid detection of sex chromosomes and the SRY gene. FISH should be used in conjunction with G-banded chromosome analysis. FISH is performed upon request when a specific numerical or structural abnormality or microdeletion is suspected. FISH is also utilized to confirm microdeletions identified during high resolution chromosome analysis and to aid in identification of abnormal chromosomes.

FISH can be performed on any specimen that can be cultured for chromosome analysis. This includes blood in a green top (sodium heparin) tube, tissue, amniotic fluid, and chorionic villus sampling (CVS). Follow collection and transport guidelines specific for each tissue type. Studies requested should be indicated at the time of sample submission. Prenatal testing will be considered on a case-by-case basis as the lab would like to ensure there is an appropriate indication before accepting a prenatal specimen for testing. Appropriate indications include abnormal ultrasound findings, abnormal NIPT result, and/or family history with a known/identified genetic etiology. Contact the laboratory prior to sending a prenatal specimen to discuss your case with a lab genetic counselor.

Will vary depending on sample type: Blood: Specimen should be kept at room temperature; do not freeze or refrigerate. Specimen should be sent by courier or overnight mail to arrive at the laboratory the next day. Amniotic Fluid and CVS: Specimen should be kept at room temperature; do not freeze or refrigerate. Specimen should be sent by courier or overnight mail to arrive at the laboratory the next day. Solid Tissue(such as skin biopsy, products of conception, or fetal tissue): Specimen should be kept at room temperature if it will be transported immediately. If specimen is not being immediately transported to the laboratory, it may be refrigerated; do not freeze. Specimen should be sent by courier or overnight mail to arrive at the laboratory the next day.

Considered on a case-by-case basis. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for most prenatal testing. Contact the laboratory prior to sending a prenatal specimen.