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Paediatric Laboratory Medicine


The SickKids Cytogenetics laboratory accepts specimens for genomic microarray testing submitted with a referral of developmental delay and/or multiple congenital anomalies.  

For more information, please see the Microarray Info Sheet

  • Specimens submitted to SickKids for genomic microarray testing must be accompanied by the SickKids-Genomic SNP Microarray Test Requistion

The above requisitions MUST be completed with the following information:

    • Name of the patient, sex, and date of birth
    • Specimen type
    • Other identifiers (SickKids number) if applicable
    • Reason(s) for referral
    • Name and signature of referring physician
    • "Clinical Description Form" for Microarray Analysis testing (see page 2 of the Genomic SNP Microarray Test requisition)

Sample Submissions

Peripheral blood in EDTA or two T25 flasks of cultured fibroblasts will be accepted for genomic microarray testing. Peripheral blood specimens in sodium heparin will not be accepted for microarray analysis.

Genomic microarray analysis may be indicated if a diagnosis is not achieved after G-band analysis.

Genomic microarray analysis will not detect polyploidy, genomic imbalances of regions that are not represented on the microarray, and low level mosaicism.

If an abnormality is identified by microarray, peripheral blood specimens for follow up FISH analyses of the patient and parents will be requested in the microarray report to assist with interpretation of the results. For follow-up FISH analyses of abnormal microarray results, specimens should be submitted along with the Constitutional Analysis Requisition.



  • Patients must have a valid Ontario Health Card number.
  • Pre-test counseling of patients and their families is recommended.
  • Genomic microarray analysis is not recommended for patients with infertility or multiple miscarriages; G-band analysis should be requested for these indications.
  • G-band/FISH analysis should continue to be requested as the front-line test for suspected aneuploidy syndromes including Down syndrome, Trisomies 13 and 18, and sex chromosome aneuploidy, or for patients with suspected chromosomal mosaicism.