A chromosomal microarray (array) is a test that looks for any pieces of chromosomes that are missing and any pieces that are extra. These changes to our chromosomes can sometimes cause health or learning concerns.

Your healthcare provider may suggest this test to look for a cause for your or your child's health or learning concerns.

An array is done on a sample of blood. It can give 4 kinds of results:

• Positive: The array found a genetic cause for your or your child's health or learning concerns. Knowing the genetic cause of these concerns can provide helpful information for you and your healthcare team.
• Negative: The array did not find anything. There could still be a genetic concern, but the array was not able to find it.
• Uncertain: The array found a change, but it is not well-understood. The change may or may not explain your health or learning concerns. Your healthcare team will talk with you about next steps to try to better underst​and this result.
• Incidental: The array found a genetic condition that is not related to your current concern. This can be surprising to learn about. Although an incidental finding does not explain your current concerns, it may still be medically important for you or your family.

Because the array only looks for missing and extra pieces of genetic material, some genetic causes for health concerns cannot be found by this test. In some cases, your healthcare team might suggest a more detailed test to look at your genes 'up close'.