Fluorescence In Situ Hybridization (FISH)
Screening for chromosomal aneuploidies of chromosomes 13, 18, 21, X, and Y in prenatal specimens
Interpretive report provided
This test does not detect aneuploidy of chromosomes other than 13, 18, 21, X, or Y. This test does not detect other chromosomal or structural anomalies.
Low levels of mosaicism involving chromosomes 13, 18, 21, X, or Y may not be detected by this procedure.
4 - 5 days
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.
1. Collect specimen by the transabdominal or transcervical method.
2. Transfer chorionic villi to a Petri dish containing transport medium (Such as CVS Media (RPMI) and Small Dish
3. Using a stereomicroscope and sterile forceps, assess the quality and quantity of the villi and remove any blood clots and maternal decidua.
4. Transfer to a sterile screw capped tube
Send to Specimen Processing refrigerated
Provide a reason for referral and gestational age with each specimen, and verify the specimen source. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.
Test performed by Mayo Medical Laboratories