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Synonyms
- Aneuploid Fluorescence in situ Hybridization
- POC FISH
Test Details
Turnaround Time
7 - 10 days
Use
This test is used for fluorescence in situ hybridization (FISH), POC aneuploid evaluation and targeting numerical changes in 13, 16, 18, 21, 22, X and Y.
Special Instructions
Refer to Paraffin FISH, POC Aneuploid [511880] for formalin-fixed or paraffin-embedded tissue. Pertinent medical findings and gestational age should accompany request for FISH. It is recommended that this test be run concurrently with Chromosome Analysis, Tissue Biopsies (Products of Conception, Skin) [052052]. Note: This test number is used for tracking FISH specimens to the testing laboratory. Bill codes will be added when testing is complete based on the processes performed in the laboratory.
Limitations
Molecular mutations below the resolution of FISH will not be detected; will not detect aneuploidy that is not targeted by FISH probes in this panel.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Fluorescence in situ hybridization (FISH)
References
Gouny C, Bonnet-Dupeyron MN, Cherasse Y, et al. Chorionic villus samples (CVS) and fluorescence in situ hybridization (FISH) for a rapid first-trimester prenatal diagnosis. Prenat Diagn. 2004 Apr; 24(4):249-256. 15065097
Tepperberg T, et al. Prenatal diagnosis using interphase fluorescence in situ hybridization (FISH): Two-year multi-center retrospective study and review of the literature. Prenat Diagn. 2001; 21:293-301.8488836
Specimen Requirements
Information on collection, storage, and volume
Specimen
Viable chorionic villi, fetal tissue, fixed-cell pellet from a cytogenetic analysis, slides from a fixed-cell pellet with metaphase and/or interphase nuclei, amniotic fluid from fetal demise
Volume
30 mg chorionic villi, 4x4x4mm fetal tissue, fixed-cell pellet from a cytogenetic analysis, 8 slides from a fixed cell pellet with metaphase and/or interphase nuclei
Minimum Volume
5 mg chorionic villi, 2x2x2mm fetal tissue, fixed-cell pellet from a cytogenetic analysis, 4 slides from a fixed cell pellet with metaphase and/or interphase nuclei; (Note: Minimum volumes may not allow for repeat testing.)
Container
Submit biopsies in a sterile tube with sterile Ringer's lactate, Hanks' basal salt solution or Labcorp transport medium.
The transport tube (a sterile specimen container with transport medium) is available from Labcorp. Please call customer service at 800-345-4363. Do not use urine containers for shipping.
Saline is not recommended for transport. Do not use urine containers for shipping.
Storage Instructions
Maintain specimen at room temperature and transport to the cytogenetics laboratory immediately. Do not freeze. Refrigerate if sterility is questioned or if sample cannot be shipped within 24 hours.
Causes for Rejection
Frozen or contaminated villi; maternal decidua received; frozen sample; absence of villi or fetal tissue; broken or stained slides; excessive cellular debris; low volume or quantity not sufficient for analysis
Collection
CVS samples: Specimen is collected in syringe (transabdominal) or catheter (transcervical) and transferred by flushing with the media from the sterile container back into it. After collecting the specimen, wash with sterile saline solution (NaCl 0.95%) containing sodium heparin (two to three drops of sodium heparin in 10 mL of saline). Carefully transfer the specimen, into the CVS transport tube, using a sterile Pasteur pipette or a sterile fine needle forceps. Be sure to fill transport tubes completely with media.
Amnio samples: Discard first 2 mL of fluid aspirated to avoid maternal cell contamination. Specimen is collected in a 20 mL sterile syringe and transferred aseptically to sterile tubes to be transported to Labcorp. Request form is completed and accompanies specimen and miscellaneous slip to the laboratory.
Fetal tissue samples: Aseptically obtain a small piece of tissue with subepidermal layers. Best results are obtained from placental villi, which remain viable much longer than fetal tissue. This is especially true in stillborn cases in which both cord blood and tissue samples are often not viable. If specimen is a product of conception, submit biopsies in a sterile tube with sterile Ringer's lactate, Hanks' basal salt solution or Labcorp transport medium.
All sample types: Transport to the testing laboratory at room temperature is acceptable. Do not allow the sample to over heat or freeze. Use a cool pack or Labcorp transport kit if necessary.