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Laboratory Test Directory

SNP Microarray Analysis (Chromosomal Microarray)

Components

Name Method Department Units
SNP Microarray Microarray analysis
Cytogenetics

Battery Members

Reflexes to FISH analysis if needed. Parental blood specimens may be requested in some cases.

Specimen Requirements

Whole blood

Container Type Container Size Specimen Volume
Required

Purple tube (EDTA)

4 mL 4 mL
Required

Green tube (Sodium heparin), No Gel

3 mL 3 mL
Stability

Room temperature - 48 hour(s)
Refrigerated - 72 hour(s)

Specimen Preparation

  • Do not centrifuge
  • Do not freeze
  • Keep at room temperature or refrigerate

Reasons for Rejection

  • Frozen specimen
  • Centrifuged specimen
  • Wrong collection tube
  • Clotted specimen

Comments

Please click on the Lab Form Link in the Forms Section to print and complete the Genetic Test Requisition Form. Submission of completed Genetic Test Requisition Form is required, and submission of informed consent form is recommended but not required.

This microarray analysis evaluates for DNA copy number abnormalities (genomic losses and gains) and large regions of homozygosity (ROH) across the genome. This test uses oligonucleotide probes as well as SNP probes. DNA copy number abnormality detection is done by comparative genomic hybridization (CGH) analysis using ~135,000 oligonucleotide probes, and ROH detection analysis is done by SNP analysis using ~67,000 SNP probes.

This test can detect submicroscopic genomic losses and gains not detectable by routine chromosome analysis (e.g. 22q11.21 microdeletion for DiGeorge syndrome, submicroscopic unbalanced translocations, etc), as well as large imbalances detectable by routine chromosome analysis (e.g. loss or gain of entire chromomosome, large unbalanced translocations/inversions). Genomic loss or gain of certain chromosomal region is known to cause or predispose to phenotypic abnormality. Some genomic loss or gain may have unknown clinical significance at this time or a unique genetic finding that is inherited within a family. If genomic loss or gain is detected, parental microarray, FISH and/or chromosome analyses may be recommended for parental diagnostic and/or recurrence risk assessment. 

Presence of ROH is not diagnostic of any disorder, but it can suggest increased risk for two different classes of genetic disorders: disorders of imprinting (uniparental disomy; UPD) and recessive genetic disorders. Evidence suggestive of a blood relationship between the parents (parental consanguinity) also may be revealed. If parental consanguinity is known, please provide reported parental relationship information on the requisition form.

PLEASE NOTE: Microarray analysis may not be able to detect the presence of mosaicism if abnormality is present in less than 30% of cells. Microarray analysis cannot detect balanced chromosomal rearrangements, such as a balanced translocation, balanced inversion, and balanced insertion.

Forms

Lab Form

CPT Code

  • 81229