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Print CPT Contact CPT coding department at 800-222-7566, ext 6-8400.
Synonyms
- Microdeletion Syndrome Analysis, Fluorescence in situ Hybridization (FISH)
Test Details
Turnaround Time
4 - 7 days
Use
Confirmation/identification of deletions below the resolution of cytogenetics (Call 800-345-4363 for list of available probes.).
Special Instructions
Pertinent clinical diagnosis, previous cytogenetic studies, and probe of interest should be included with the specimen.
Methodology
Fluorescence in situ hybridization (FISH)
Specimen Requirements
Information on collection, storage, and volume
Specimen
Fixed-cell pellet from a cytogenetic analysis, slides with metaphases and/or interphase nuclei for each probe indicated, blood, bone marrow, amniotic fluid, chorionic villi/products of conception or slides from buccal smears
Volume
Fixed-cell pellet, three slides, 10 mL blood (adult), 5 mL blood (pediatric), 3 mL bone marrow, or 10 mL amniotic fluid
Minimum Volume
Fixed-cell pellet from a cytogenetic analysis, two slides, 5 mL blood (adult), 1 mL blood (pediatric), 1 mL bone marrow, or 5 mL amniotic fluid
Container
All blood or bone marrow in sodium heparin tube (pediatric Vacutainer® is optimal), confluent T-25 flask (amniotic fluid)
Storage Instructions
Maintain specimens at room temperature.
Causes for Rejection
Broken or dirty slides; excessive cellular debris; stains on slides
Collection
When buccal smears are used to make slides, follow these instructions:
• Have the patient rinse the oral cavity twice with drinking water.
• Scrape the inside of the oral cavity well using only one side of the premoistened applicator. A cotton swab can be used if an applicator is not available. Discard first scraping and repeat with slightly more pressure.
• Smear the collected specimen gently and evenly across a prelabeled glass slide.
• Allow the slide to air-dry at room temperature for 10 to 30 minutes. Check the quality of the slide with phase microscopy, if available, before proceeding. A good slide has 30−100 cells/lpf and appropriate morphology (ie, lying flat, no residue or film, not refractile, gray in color).
• Dip the slide(s) in a Coplin jar with 50% methanol/50% acetic acid for ten minutes (or spray with a cytology spray) and air-dry.