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International Birth Defects Information System



FLUORESCENCE IN SITU HYBRIDIZATION (FISH) ANALYSIS

FISH to Rule Out Specific Trisomies

Probes available: Chromosome 21; Chromosome 13; Chromosome 18; Chromosome 12; X and Y Chromosomes (Other probes may be available upon request).

Involves hybridization of chromosome-specific DNA probes to uncultured cells to detect specific trisomies. Must be done in conjunction with routine chromosome analyses unless chromosome analysis has been done previously.


Peripheral Blood:

Specimen Requirements: 5-10 cc blood (1-2 cc for newborns) in a green top tube (sodium heparin). Mix well by inverting. Maintain specimen at room temperature. Fixed cells from a previous cytogenetic study can be used. Contact the laboratory to check the availability of fixed cells.


Amniotic Fluid:

Specimen Requirements: Performed only in conjunction with routine amniotic fluid chromosome studies. Draw 10 cc above amount for routine chromosomes study - minimum of 30cc.


Bone Marrow:

Specimen Requirements: Indicate peripheral blood WBC and % blasts on request form. Bone marrow for cytogenetics should be obtained from the second aspirate. Draw 1-2 cc into a syringe "wetted" with sodium heparin (500 U heparin/cc). Invert syringe to mix with heparin. Immediately add specimen to a tube containing 5-10 ml sterile culture medium. Mix contents of tube well by inverting. Cap tightly and cover with Parafilm. Keep cool (do not freeze). Deliver to laboratory as soon as possible.


Skin:

Specimen Requirements: Biopsy site should be cleaned using a sterile gauze pad saturated with acetone. DO NOT use antiseptic soaps or iodine. Allow to dry. If local anesthetic is used, we recommend a lidocaine solution without epinephrine. Obtain a piece of skin (full thickness) 3-5 mm in diameter. Transfer specimen to a tube containing tissue culture medium [preferred] or sterile isotonic saline solution (tubes available upon request). Fill tube completely. Cap tightly and seal with Parafilm. Refrigerate specimen until shipment (do not freeze).

Turn Around Time:24-48 hrs.


FISH to Rule Out Microdeletions or Translocations

Probes available: DiGeorge synd., Williams synd., Smith-Magenis synd., Miller-Dieker synd., Cri du Chat synd., Retinoblastoma, BCR/ABL inv(16), T(11;14), T(15;17)(Other probes may be available upon request.)

Involves use of DNA probes that hybridize to specific genes or chromosome regions to test for small deletions or translocations. Usually done in conjunction with routine chromosome analysis unless chromosome analysis has been done previously.


Peripheral Blood:

Specimen Requirements: 5-10 cc blood (1-2 cc for newborns) in a green top tube (sodium heparin). Mix well by inverting. Maintain specimen at room temperature. Fixed cells from a previous cytogenetic study can be used. Contact the laboratory to check the availability of fixed cells.


Amniotic Fluid:

Specimen Requirements: Performed only in conjunction with routine amniotic fluid chromosome studies. Draw 10 cc above amount for routine chromosomes study - minimum of 30cc.


Bone Marrow:

Specimen Requirements: Indicate peripheral blood WBC and % blasts on request form. Bone marrow for cytogenetics should be obtained from the second aspirate. Draw 1-2 cc into a syringe "wetted" with sodium heparin (500 U heparin/cc). Invert syringe to mix with heparin. Immediately add specimen to a tube containing 5-10 ml sterile culture medium. Mix contents of tube well by inverting. Cap tightly and cover with Parafilm. Keep cool (do not freeze). Deliver to laboratory as soon as possible.


Skin:

Specimen Requirements: Biopsy site should be cleaned using a sterile gauze pad saturated with acetone. DO NOT use antiseptic soaps or iodine. Allow to dry. If local anesthetic is used, we recommend a lidocaine solution without epinephrine. Obtain a piece of skin (full thickness) 3-5 mm in diameter. Transfer specimen to a tube containing tissue culture medium [preferred] or sterile isotonic saline solution (tubes available upon request). Fill tube completely. Cap tightly and seal with Parafilm. Refrigerate specimen until shipment (do not freeze).

Turn Around Time: Depends on tissue type but generally 7-21 days.



FISH Only: Previous chromosome study required

Peripheral Blood:

Specimen Requirements: 5-10 cc blood (1-2 cc for newborns) in a green top tube (sodium heparin). Mix well by inverting. Maintain specimen at room temperature. Fixed cells from a previous cytogenetic study can be used. Contact the laboratory to check the availability of fixed cells.


Amniotic Fluid:

Specimen Requirements: Performed only after consultation with laboratory director. Call for information.


Bone Marrow:

Specimen Requirements: Indicate peripheral blood WBC and % blasts on request form. Bone marrow for cytogenetics should be obtained from the second aspirate. Draw 1-2 cc into a syringe "wetted" with sodium heparin (500 U heparin/cc). Invert syringe to mix with heparin. Immediately add specimen to a tube containing 5-10 ml sterile culture medium (e.g. RPMI 1640 or MEM). Mix contents of tube well by inverting. Cap tightly and cover with Parafilm. Keep cool (do not freeze). Deliver to laboratory as soon as possible.


Skin:

Specimen Requirements: Biopsy site should be cleaned using a sterile gauze pad saturated with acetone. DO NOT use antiseptic soaps (Betadine, Hibitane) or iodine. Allow to dry. If local anesthetic is used, we recommend a lidocaine solution without epinephrine. Obtain a piece of skin (full thickness) 3-5 mm in diameter. Transfer specimen to a tube containing tissue culture medium [preferred] or sterile isotonic saline solution (tubes available upon request). Fill tube completely. Cap tightly and seal with Parafilm. Refrigerate specimen until shipment (do not freeze).

If fixed cells from a previous chromosome study are available, no specimen is required. Contact the laboratory to check on the availability of fixed cells.


Turn Around Time: Depends on tissue type. If fixed cells are available, 2-7 days.



For more information please call us or  email  us .


University of South Alabama
Birth Defects Genetics Center - Mobile, Alabama 36688-0002 / 251-460-7500
For questions or comments contact us or call toll free 1-800-624-1865
Date last changed: August 4, 2004
http://www.southalabama.edu/genetics