Pretest Counseling for CMA

As with all shared medical decision-making, the pre-test counseling process for CMA should include a discussion of limitations, risks, benefits and alternatives. While this is true for all genetic tests, you may find that the nature of CMA testing leads to a few considerations that you may not be used to discussing. Here we outline strategies and resources to focus and facilitate patient/family counseling about CMA.

How do I educate about CMA?

What kind of language should I use in pre-test education?

Use the same considerations as you do when discussing any genetic test with families.  Even families who are familiar with a few genetics terms may hold misconceptions reinforced by popular media and family stories. When possible:

  • Avoid medical jargon
  • Define unfamiliar terms
  • Provide concrete examples for abstract ideas
  • Use person-centered, rather than disease-focused terms
  • Reinforce the commonality of genetic variation

 Sample Language

Instead of saying this: Try this:


Missing or extra genetic information


All of the genetic material


Genetic difference

Test sensitivity

Chance of detecting a variant


Passed from parent to child

Strong or high risk

X% chance, or 1 in X

Down syndrome child

Child with Down syndrome


What tools are useful in pre-test education?

Whenever possible use illustrations to enhance patient counseling. Visual aids on general genetics concepts are available from genetics organizations. Many laboratories also provide visual aids specifically about CMA testing.

Photos showing features of different microdeletion/microduplication syndromes can help families visualize the implications of these variants. When possible, use naturalistic photos in non-medical settings, rather than clinical and textbook photos.

What do I tell families

Why not wait to educate them when we have the results?

Pre-test counseling is an opportunity to provide a foundation for families to later understand and adjust to results. Consider the following:

  • Families who are made aware of potential risks and limitations may adapt more easily if those situations arise.
  • Providing both pre- and post-test counseling allows time for processing and repetition, which improve the learning of new concepts.
  • Heightened emotions at the time of result disclosure can inhibit integration of new information.
  • Pre-test counseling gives patients/families an opportunity to opt-out or choose an alternative if the potential outcomes of testing do not match their goals or values
  • Pre-test counseling helps build rapport and identify pre-existing issues that may complicate understanding or adaptation to results.

What information is critical for patients/families before testing?

At a minimum, families should understand:

  • The test detects extra or missing genetic material, which may be associated with health and developmental problems.
  • 15-20% of the time, the test detects a genetic difference in patients with intellectual disability, congenital birth defects, and/or autism.
  • 5-8% of the time, the test detects a genetic difference we don’t know much about, leaving us with some uncertainty about whether it is the cause of a patient's health problems.
  • Parental testing may be indicated to determine whether a genetic difference was passed from parent to child in order to better understand the clinical significance of a CNV.  This could reveal unexpected information about family relationships, such as nonpaternity.
  • Because CMA covers chromosomal regions across the whole genome, less than 1% of the time it detects genetic differences linked to health problems unrelated to the original reason for testing.
  • Certain types of CMA may detect evidence of a biological relationship between the parents (consanguinity).
  • CMA does not detect ALL types of genetic changes, so a negative result doesn’t rule out a genetic etiology for the person’s symptoms. Additional testing maybe needed depending on the suspected diagnosis.

Many families will also need a foundation in basic genetics concepts, including what genes are and how they are passed from generation to generation. Use your clinical judgment to gauge the amount of detail a patient/family can absorb and what facts are most relevant to a family’s concerns.

Families will also benefit from an outline of expectations for the testing process, such as timing and how results will be disclosed.  In addition, typical elements of informed consent apply to CMA testing. Remember, informed consent is a process, not just a document, so it is best to allow time for discussion.

How do I prepare families for outcomes?

Set realistic expectations

A family’s understanding of CMA may be influenced by past experience with vastly different tests. You can help adjust expectations by using explicit and jargon-free language to describe the test.

Also consider how you might handle incidental findings. An incidental finding is the discovery of a variant that has health implications unrelated to the original indication for testing. While uncommon, these findings may come as a surprise to the family.  Discussing the possibility explicitly may help the family better understand the broader implications of CMA.

Have a clear plan for testing and disclosure

Having a plan for testing and disclosure may seem like a small detail. However, this step can give a family a sense of control, reduce anxiety, and avoid confusion. When possible, elicit and accommodate family preferences regarding timing and setting. Help families think through what environment will be most conducive to learning and emotional support.  The plan should include:

  • When the sample will be obtained
  • How the sample will be obtained
  • When the results will be disclosed
  • Where the discussion will occur (in the clinic, in an office, over the phone)
  • Who will be present (including health care providers, family, friends, other support)
  • Who will be informed of the results (other health care providers, family)

Anticipate psychosocial responses and needs

Concepts surrounding family, inheritance, and susceptibility to disease can be emotionally laden. Genetic counseling research suggests that the potential for uncertainty inherent in CMA testing can generate unanticipated psychosocial challenges for families. Help them prepare ahead of time by:

  • Eliciting how they might respond to different results ahead of time
  • Examining how results might impact other family members
  • Exploring family communication patterns
  • Considering cultural differences that may impact response to results
  • Identifying potential support resources that can be called upon in the future