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Team Evaluates Impact of Chromosomal Microarray Analysis on Clinical Management Decisions


Chromosomal microarray analysis may be widely regarded as a first-tier method for both pediatric and prenatal cytogenetic testing, but that hasn't convinced some insurers to reimburse such tests.

The American College of Medical Genetics and Genomics, the Society for Maternal-Fetal Medicine, and the American College of Obstetricians and Gynecologists have all updated their guidelines to recommend CMA in certain situations, making the array-based approach the widely considered standard of care.

However, "a lot of insurance companies still believe that CMA is experimental and will not affect any clinical management," Denise Batista, director of the cytogenetics laboratory at the Kennedy Krieger Institute in Baltimore told BioArray News. "We wanted to show that that's not the case."

Batista is the corresponding author on a study published this month in Genetics in Medicine. In it, Batista and colleagues at Johns Hopkins University and the McKusick-Nathans Institute of Genetic Medicine conducted a retrospective analysis of three years' worth of cases to assess to what extent abnormal CMA findings were followed by clinical management decisions.

As highlighted in the paper, the authors reviewed the electronic medical records of all patients who had abnormal chromosomal microarray findings reported by KKI's laboratory and quantified the management recommendations made in response to these results. They found that CMA had an impact on care in more than half of cases where an abnormal finding was reported.

More specifically, according to the study, abnormal chromosomal microarray findings were reported for 12.7 percent of patients, or 227 out of 1,780 cases evaluated. For patients with clinical follow-up notes available, the CMA results had management implications for 102 out of 187 patients, or 54.5 percent, in the entire abnormal cohort, – as well as for 16 out of 38 patients, or 42.1 percent, referred for isolated neurodevelopmental disorders.

The authors listed such recommendations as including pharmacological treatment, cancer-related screening or exclusion of screening, contraindications, and referrals for further evaluation.

"These results empirically demonstrate the clinical utility of chromosomal microarrays by providing evidence that management was directly affected for the majority of patients in our cohort with abnormal chromosomal microarray findings," the authors concluded.

"It was very important for us to put out that kind of information for clinicians and also for insurance companies," Batista said. "First of all, CMA has been used for 10 years and so many labs have used it for molecular diagnostics," she said. "So it is definitely affecting clinical management and that is what we wanted to show," she added.

Batista noted that such management decisions will likely increase as abnormal CMA findings are better understood by the cytogenetics community. "We will be making more management decisions about the arrays as we learn more about these syndromes," she said.

But even with such results, she said that some insurers are hesitant to reimburse the tests given their higher head-to-head cost in comparison with traditional, microscope-slide-based karyotyping, as well as the fact that they is performed using a newer technology.

Batista, in particular, took issue with the perception of CMA being a new approach for cytogeneticists.

"The insurance companies don't want to pay for new technology, but this isn't new. It's been around for a decade or more," she said. Instead, she believes the new paper might aid geneticists who are appealing for reimbursement, and can cite the paper's findings in arguments about why CMA should be reimbursed.

"This will give the genetic counselors ammunition to write letters of necessity to insurance companies that don't want to pay, so they will have more data to get insurers to pay," said Batista. "That was our intention – to get real data so that people could challenge insurance companies to pay for it."

While Batista and colleagues achieved what they set out to accomplish – demonstrating that CMA results do lead to clinical management decisions – she said it was possible that they could study the issue further in future efforts. Specifically, they could determine to what extent recommendations based on CMA findings that altered clinical management had benefitted patients in the end.

"We could do a follow up to see, of all those management decisions were made, which ones were followed, and how many gave meaningful results," she said.