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Pathology and Laboratory Medicine
Test Catalogue

​Fluorescence in situ Hybridization (FISH) - Blood


​Ordering Recommendation

  • ​ ​Preferred collection times are Monday , Tuesday and Friday

​ ​Specimen Requirements

  • ​Peripheral blood/ whole blood
​Collection Procedure
  • ​Invert several times to mix
  • Other anticoagulants are not recommended since they are harmful to the viability of the cells
  • Specimen must be accompanied by a completed test requisition
  • Failure to include relevant patient information may result in test results being delayed or discontinued
​Required Volume
  • ​Optimal Volume: 5-7 ml
  • Minimum Volume: 1 ml for neonates; 2 ml for all other patients
    (Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection.)
  • Pediatric Volume: 1-3 ml of peripheral blood or cord blood
  • ​Specimens are to be kept and delivered at room temperature
  • Do not freeze specimen or expose to extreme heat
Grounds for Rejection​

Testing Information​ ​

  • ​Specimens are received in the Cytogenetics Laboratory weekdays from 8:00 a.m. to 5:00 p.m.
  • Cultures are routinely initiated Mondays, Tuesdays and Fridays. Neonate cultures can be initiated on other days.
  • There is a Cytogenetics technologist on call Saturday, Sunday and statutory holidays from 8:30 a.m. to 5:00 p.m. for urgent specimens only. This person can be reached through Royal University Hospital Switchboard (655-1000)
  • Specimens to be received the day before a long weekend or during the Christmas/ New Year or Easter Holidays must be approved with the Laboratory before sending
  • Booking of specimens from outside the Saskatoon Health Region is recommended for tracking purposes
Testing Site​Cytogenetics Laboratory
Ellis Hall Ground Floor, Room 35
Royal University Hospital, 103 Hospital Drive
Saskatoon SK S7N 0W8
Phone: 306-655-1706
FAX: 306-655-6462
Results Reporting​
  • ​Dependent on specimen type, indication and workload
  • STAT and urgent specimens are reported within 14 days
​Reflex Testing
  • ​National guidelines require a concurrent chromosome analysis in most cases
  • ​PHA-stimulated lymphocyte culture and fluorescence in situ hybridization (FISH) with commercially available probes
​Clinical Interpretation
  • ​Diagnosis of microdeletion syndromes
  • Anomaly designation follows the most recent edition of the International System for Human Cytogenetic Nomenclature
​Specimen Retention
  • ​Original peripheral blood specimen: two weeks
  • Cell suspension: two months after reporting
  • FISH slide(s): six months
Alternate Test Names​
  • FISH
​Additional Comments
  • ​The test is not appropriate for acquired hematological disorders (see Chromosome analysis – Bone Marrow)
  • Molecular genetics (DNA) testing is only done through referral to Medical Genetics (phone: 655-1692)
Reference Ranges​
  • Two copies of the probe at the expected chromosome location

Testing Ordering Requirements​ ​

​Forms Required

Patient History​ ​

​Relevant Clinical History
  • ​Clinical features of Wolf-Hirschhorn, Cri-du-chat, Williams, Smith-Magenis, Miller-Dieker, DiGeorge/ Velocardiofacial, Kallman syndromes; lchthyosis or Steroid Sulfatase deficiency
  • Clinical features of Prader-Willi or Angelman syndrome after testing for imprinting of the 15q11.2 chromosomal region
  • SRY study in some disorders of sexual development
  • Parental study in cases with a positive diagnosis

​If you choose to print this information, it is valid only on date of print.

Laboratory Controlled Document LSM-163 v3

Last Modified: Monday, December 11, 2017 |
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