Prenatal chromosomal microarray analysis | CMA

Test DetailsAffymetrix CytoScan HD assay with genomic DNA extraction to detect small gains and losses across the entire genome. A genomic imbalance is always reported when a copy number gain is at least 2 Mb or a copy number loss is at least 1 Mb, unless it represents a region clearly associated with benign copy number polymorphism in multiple independent studies. A copy number loss smaller than 1 Mb or a copy number gain smaller than 2 Mb may not be reported, unless it involves a region of the genome with established clinical significance. Regions of homozygosity (ROH) are reported when they are at least 10 Mb. For cases of ROH in multiple chromosomes, with suspected consanguinity, all regions greater than 5Mb will be reported. Chromosome analysis will detect large balanced rearrangements.
MethodologyChromosomal microarray analysis
PerformedMonday – Friday
Turnaround21 – 28 days
Specimen RequirementsAmniotic fluid (AF), chorionic villi sampling (CVS), percutaneous umbilical blood sampling (PUBS)
Sample CollectionAF: Discard first 2mL of amniotic fluid. Collect 15-25mL in a sterile syringe. Use sterile technique to transfer to 15mL sterile screw-top plastic conical tubes for transport. Do not centrifuge. CVS: Collect 15-40mg of budding villi in 50mL screw-top plastic conical tubes in sterile transport media (provided by cytogenetics lab). Do not centrifuge. PUBS: Collect 1-3mL in sterile, 15mL sodium heparin (green-top) Vacutainer tube. Collect under ultrasound guidance. Invert tube immediately upon completion of blood collection to prevent formation of clots.
Storage/Transport ConditionsRoom temperature
Unacceptable ConditionsWill not be accepted after three days
Special InstructionsRefrigerate if sample cannot be delivered within 24 hours; Uniquely identify twins/multiples
CPT Code(s)81229 x 1, 88235 x 1, 88291 x 1, 88280 x 1, 88261 x 1