Test name: PRENATAL FISH including Rapid Aneuploidy FISH and/or Constitutional (Targeted) FISH
Also known as: Fluorescence in situ hybridization (FISH), trisomy panel or FISH for aneuploidy, FISH for microdeletions/microduplications
Rapid Aneuploidy FISH
Advanced maternal age (> 35 years of age).
Abnormal prenatal screen for Down syndrome, Trisomy 18/1.
Ultrasound findings suggestive of Down syndrome, Trisomy 18 or 13 and/or triploidy.
Fluorescence in situ hybridization (FISH) is used to detect approximately 99% of +13, +18, +21 and aneuploidies of X & Y.
Rapid Aneuploidy FISH is not designed to detect structural chromosome abnormalities and mosaicism can lead to inconclusive results in some situations.
Prenatal Chromosome Analysis is required on the same specimen.
Constitutional (Targeted) FISH
See list below for current probes
Prenatal ultrasound findings suggestive of a specific microdeletion or microduplication condition listed below.
Known familial chromosome rearrangement.
Fluorescence in situ hybridization (FISH) tests can be ordered individually. This test is recommended in conjunction with Prenatal Chromosome Analysis.
Note: all of these microdeletion/microduplication conditions are also identified on the Prenatal Microarray.
Current list of HGL CONSTITUTIONAL (Targeted) FISH tests
(* = Home-brew probes)
Pallister-Killian Syndrome [12p]
Human multicolor (M-FISH)
|Subtelomere analysis for each chromosome
Whole chromosome Paint Probes
|All probes in the FISH test catalog above are available for assessment of chromosomal abnormalities based on family history or suspicious/abnormal cytogenetic findings. Please contact the laboratory for case-specific probe availability.|
Additional prenatal tests available (refer to additional pages for details):
Prenatal Chromosome Analysis (required)
CMV, Toxoplasmosis, and Parvovirus B19 testing is sent out
Single Gene Testing: If additional single gene testing is considered for a familial genetic condition or abnormal ultrasound findings, contact a laboratory genetic counselor prior to sending the sample for coordination of testing.
Specimen requirements: Prenatal Chromosome Analysis for confirmation and clarification of trisomy, translocation, or mosaicism of 13, 18, 21 or sex chromosome differences is required in conjunction with Rapid Aneuploidy FISH. Prenatal Chromosome Analysis is recommended in conjunction with any Constitutional (Targeted) FISH.
• CVS: 10-15 mg in sterile tissue culture media (amount sufficient for FISH and Prenatal Chromosome Analysis)
• Amniotic Fluid: 5 ml of additional amniotic fluid for FISH. Total fluid needed for both Prenatal Chromosome Analysis and Rapid Aneuploidy FISH is 20-25 ml
CPT codes: Due to the complexity, call 402-559-5070, option 3, if clarification is needed.
- Aneuploidy screen: 88271(x5), 88275(x2), 88291
Aneuploidy screen with 22q11.2 analysis:88271(x7), 88275(x3), 88291
- Locus-specific testing for Constitutional (Targeted) FISH
One chromosomal target: 88271(x1-3), 88275, 88291
For each additional chromosomal target: 88271(x1-2), 88275(x0-1) plus the “One chromosomal target” CPT codes listed above
Pricing: Contact the laboratory billing staff for current costs
Required forms: Prenatal Test Request Form
Turn-around time: Results are typically available in 24-48 hours for Rapid Aneuploidy FISH and 22q. Results for other Constitutional (Targeted) FISH added as a result of abnormal Cytogenetic findings may take 7-14 days.