Microdeletion analysis (prenatal) | FISH
| Test Details | Detects microdeletions: DiGeorge – Tuple1; Williams – ELN; Prader-Willi – SNRPN; Angelman – S10; Cri du Chat – EGR1; Wolf-Hirschhorn – WHS; Miller-Dieker – LIS1; Smith-Magenis – SMS; Steroid Sulfatase Deficiency – STS; SRY deletion – SRY/CEP X; sex chromosomes – CEP XY |
| Methodology | Fluorescence in-situ hybridization |
| Performed | Monday – Saturday |
| Turnaround | 10 – 21 days |
| Specimen requirements | Amniotic fluid (AF), chorionic villi sampling (CVS), percutaneous umbilical blood sampling (PUBS) |
| Sample collection | AF: Discard first 2mL of amniotic fluid. Collect 15-25mL in a sterile syringe. Use sterile technique to transfer to 15mL sterile screw-top plastic conical tubes for transport. Do not centrifuge. CVS: Collect 15-40mg of budding villi in 50mL screw-top plastic conical tubes in sterile transport media (provided by cytogenetics lab). Do not centrifuge. PUBS: Collect 1-3mL in sterile, 15mL sodium heparin (green-top) Vacutainer tube. Collect under ultrasound guidance. Invert tube immediately upon completion of blood collection to prevent formation of clots. |
| Minimum sample volume | 10 mLs |
| Storage/Transport Conditions | Room temperature |
| Unacceptable Conditions | Will not be accepted after three days |
| Special Instructions | Refrigerate if sample cannot be delivered within 24 hours; Send to Rapid Response or SLCH Central Receiving |
| CPT Code(s) | 88291×1, 88235×1, 88271×2, 88273×1, 88274×1 |