Prenatal Aneuploidy Detection, FISH
Use
Screening for chromosomal aneuploidies of chromosomes 13, 18, 21, X, and Y in prenatal specimens. Techniques to detect aneuploidy include standard chromosome analysis and fluorescence in situ hybridization (FISH). Standard chromosome analysis from amniotic fluid cells or chorionic villi requires 5 to 9 days for culture, harvest, and analysis. FISH can rapidly detect aneuploidy of 13, 18, 21, X, and Y in uncultured amniotic fluid cells or chorionic villi. It is helpful in medically urgent evaluations of newborn infants suspected to have aneuploidy of any of these chromosomes.
Special Instructions
A reason for testing is requested with each specimen. The laboratory will not reject testing if this information is not provided; however, appropriate testing or interpretation may be compromised or delayed in some instances. If not provided, an appropriate indication for testing may be entered by Mayo Clinic Laboratories.
Limitations
This test does not detect aneuploidy of chromosomes other than 13, 18, 21, X, or Y. Additionally, it does not detect other chromosomal or structural anomalies and is intended to be ordered in conjunction with chromosomal microarray or chromosome analysis. Low levels of mosaicism involving chromosomes 13, 18, 21, X, or Y may not be detected by this procedure. A normal result does not rule out the possibility of birth defects, such as those caused by non-targeted chromosome abnormalities, submicroscopic cytogenetic abnormalities, pathogenic molecular variants, and environmental factors (i.e., teratogen exposure).
New York Approved
Methodology
Chromosomal / Cytogenetics (FISH)
Biomarkers
LOINC Codes
- 57317-0
- 50397-9
- 69965-2
- 57317-0
- 42349-1
- 31208-2
- 85069-3
Result Turnaround Time
3-4 days
Related Documents
For more information, please review the documents below
Specimen
Amniotic Fluid
Volume
20 to 25 mL
Minimum Volume
2 mL
Container
Amniotic fluid container
Collection Instructions
1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted. Provide gestational age at the time of amniocentesis. 2. Discard the first 2 mL of amniotic fluid. 3. If ordering with CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling, submit a minimum of 12 mL. 4. If ordering with CHRAF / Chromosome Analysis, Amniotic Fluid, submit a minimum of 12 mL. 5. If ordering with both CMAP and CHRAF, then submit a minimum of 26 mL.
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | Refrigerated (preferred) |