Benefits of chromosomal microarray testing

Chromosomal microarray testing for greater diagnostic yield and greater savings

In July 2013, Dr. Hofherr's group at the Molecular Diagnostics Laboratory within the Children's National Health System brought chromosomal microarray analysis (CMA) in-house. This move decreased the lab's send-out testing by 50%, resulting in an annual saving of over $250,000. One year later, they transitioned to CytoScan Dx Assay, the first FDA-cleared whole-genome chromosomal microarray test to aid in identifying the underlying genetic cause of developmental delay, intellectual disability, congenital anomalies, and dysmorphic features in children. Their initial studies with CytoScan Dx Assay resulted in 28% diagnostic yield.

Prior to transitioning to chromosomal microarray testing and CytoScan Dx Assay, Children's National Health Diagnostics Laboratory was sending more than 90% of its genetic test requests to outside labs. The outsourcing procedures were complex, disorganized, and costly. Providers and patients were often denied insurance pre-authorization because the tests in use were not FDA-cleared.

As of April 2015, the team had completed in-house microarray testing on 1000 cases. After the transition to CytoScan Dx Assay, 346 patients with suspected chromosomal disorders were tested. Those tests revealed 99 patients with clinically relevant aberrations, including 74 with copy number variations (CNVs) and 25 with absence of heterozygosity (AOH). Some of the CNVs were considered atypical and would have been missed with conventional fluorescent in situ hybridization (FISH) testing. The CMA results also identified targeted areas of homozygosity for the lab's next-generation sequencing (NGS) pipeline.

Since implementing the FDA-cleared CytoScan Dx Assay in-house, the lab has noticed a significant decrease in denials, appeals, and peer-to-peer requests for CMA testing. The lab expects that with this test, providers will spend less time obtaining authorization and patients will have a better chance of obtaining coverage.

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