NB: Sample for chromosome analysis may be collected and sent at same time as sample for RAD. Include comment on requisition that sample is for possible follow-up to RAD only. Cytogenetic sample will be held until RAD results are available, and may be discontinued if chromosome analysis is not required.

If karyotype is required for mechanistic information only, chromosome analysis may be performed in lieu of RAD testing. Turnaround time for karyotyping is 3 – 4 weeks. Please indicate on requisition that cytogenetic testing is for mechanistic information only.

CLINICAL INDICATION

• Suspicion of common aneuploidy (Trisomy 13, 18, 21 and X/Y chromosomes), or mosaicism*

• Ambiguous genitalia/ sex determination

TESTING

Rapid Aneuploidy Detection (RAD)

(see below for follow-up testing information)

LABORATORY REQUISITION REQUIRED

• IWK Clinical Genomics Genetic Testing General Requisition

  • Instructions for Genetic Testing General Requisition

  • Molecular Testing Section

SAMPLE REQUIREMENTS

3-5 ml peripheral blood in EDTA (purple top) tube

(2 ml peripheral blood (EDTA) from newborn < 1 mo.)

All specimens must be sent with a completed requisition. Specimen and requisition must both be labelled with the following matching identifiers:

• Patient's full name (first and last)
  AND

• Patient's Health Card Number or Hospital Identification Number

Any specimens received without the appropriate requisition or identifiers may be rejected.

TURN AROUND TIME

Newborns/ other STAT testing: 5 days

Routine: 14 days

OPTIONAL FOLLOW UP TESTING

• Abnormal RAD: Cytogenetic Testing

• Normal RAD AND the patient presents with any of the following clinical features: intellectual disability, developmental delay, multiple congenital anomalies, dysmorphism and autism/autistic spectrum disorders: Microarray Testing

• Normal RAD AND suspicion of chromosomal rearrangement of sex chromosomes: Cytogenetic Testing

*RAD and Microarray can detect mosaicism up to 20%

Direct all samples to Clinical Genomics Laboratory, IWK Health Centre
5850/5980 University Ave, PO Box 9700, Halifax, NS, B3K 6R8
For more information, email (preferred): clinicalgenomics@iwk.nshealth.ca or call 902-470-6504.