Update Type: Test Methodology Changed
Test Updated: 06/21/2023
Test Overview
Test Methodology

This Chromosomal Microarray (CMA) analysis uses the Illumina Global Diversity Array with Cytogenetics (GDAC) content. The GDAC uses approximately 1.8M markers for high exon coverage in targeted regions to detect various types and sizes of structural genomic variation in the human genome. Patient DNA is isolated, linearly amplified, enzymatically fragmented, and hybridized to array probes. Each hybridized array probe is extended with tagged terminating nucleotides. The extended probes are stained, and the array is washed, scanned, and the results are analyzed and interpreted. Only clinically significant copy number variants (CNVs) and/or regions of homozygosity (ROHs) will be reported.

Test Usage

This Chromosomal Microarray (CMA) assay detects copy number variants (CNVs) and regions of homozygosity (ROHs) in genomic DNA. The American College of Medical Genetics (ACMG) recommends chromosomal microarray (CMA) as the first-line genetic test for all children with autism spectrum disorders and other developmental / intellectual disabilities or birth defects (Manning et al. Gene Med. 2010. 12:742-745. PMID: 20962661). By using CMA testing, a patient’s genomic DNA is examined for gains or losses that are too small to be detected by standard G-banded chromosome studies. The increased resolution of CMA technology over conventional cytogenetic analysis allows for identification of chromosomal imbalances with greater precision, accuracy, and technical sensitivity. Therefore, this CMA assay is a more cost-effective alternative to sequential or multiplex FISH for subtelomeric deletions. This CMA assay is used to detect various types and sizes of structural genomic variation in the human genome including deletions, duplications, regions of SNP homozygosity, Uniparental Disomy (UPD), and mosaicism. This CMA analysis is recommended to test patients with Mendelian conditions or syndromes, dysmorphic features, congenital anomalies, developmental delays, cognitive impairments, and autism spectrum disorders (Martin CL, Ledbetter DH. JAMA. 2017;317:2545-2546. PMID: 28654998).

Reference Range *

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

CMA may not detect low-level mosaicism and cannot detect chromosomal aberrations that do not result in net gains or losses of genomic material, such as balanced chromosomal rearrangements (balanced translocations, balanced insertions, and inversions), rearrangements in repeat sequences (short arms of acrocentric chromosomes and heterochromatic regions), point mutations, indels, and epigenetic alterations. CMA will not detect genomic imbalances in regions that are not represented on the array. Interpretation of CMA results can be complicated by the detection of genomic copy number changes of unknown clinical significance. These copy number variants of unknown clinical significance can be family or population specific and may require further studies, including analysis of parental samples and further medical genetic evaluation. For common aneuploidy (e.g., trisomy 21 or trisomy 13) conventional karyotyping may be more appropriate and cost-effective.

Test Details
Days Set Up
Monday - Friday
Analytic Time

28 days

Soft Order Code
MiChart Code
SNP Chromosomal Microarray Analysis
  • Array CGH (aCGH)
  • Comparative Genomic Hybridization
  • CGH
  • Microarray CGH
  • CMA
  • SNP Array
  • Generic Peds Genetics Test
  • CMAB2
  • CMAB1
  • Array CGH (Post-Natal) Shadow
  • Array CGH 2 (Post-Natal) Shado
  • Chromosomal Microarray Shadow
  • CMAB1S
  • CMAB2S
  • SNP CMA Analysis
  • SNPM1
  • SNPM1S
  • SNP CMA Analysis Shadow
  • Germline
MMGL Molecular Genetics
Specimen Requirements
Collection Instructions

Collect specimen in a lavender top tube. Send intact specimen within 24 hours if stored at room temperature or within 5 days if stored refrigerated. Include the patient's family history, pedigree, and ethnicity on the test requisition. Obtaining informed consent from the patient prior to testing is recommended. For a UMHS Request and Consent for Genetic Testing form, contact the MLabs Client Services Center at 800-862-7284 or online at https://mlabs.umich.edu/media/188.

CMA should not be ordered for phenotypically normal individuals with a family history of a balanced chromosome rearrangement.
Normal Volume
5 - 10 mL EDTA whole blood
Minimum Volume
2 mL EDTA whole blood
Rejection Criteria
Fresh tissue (POC) or paraffin embedded specimens are not acceptable.
Additional Information

By ordering this test the clinician acknowledges that additional reflex testing (e.g., Prader-Willi/Angleman and other imprinting disorders due to potential UPD, etc) may be performed and billed at a separate additional charge if indicated. Chromosomal Microarray (CMA) analysis is more sensitive than conventional karyotyping. CMA will provide a clinically relevant result in at least 5-17% of individuals with mental retardation and/or developmental problems who have an apparently normal karyotype by conventional cytogenetic and may be able to identify specific loci/genes involved in a genomic imbalance. By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes medical geneticist interpretation of results billed as a separate additional charge. This test is not available without interpretation.

CPT Code
Fee Code
Pro Fee CPT