Genetic Testing Results Interpretation Tool

Key Points When Interpreting Genetic Test Results

  • The interpretation of a genetic result depends on the context of the individual and family. 
  • If a patient meets clinical criteria for a genetic syndrome based on his or her medical and family history, the patient may be screened and managed according to guidelines for the syndrome, even in the absence of confirmatory genetic testing.
  • When testing an unaffected relative, negative results are not fully informative unless a mutation has already been identified in the family.
  • Genetic test results are not always straightforward. Be cautious with counseling and management changes when results are uninformative or VUS. In these cases, consider communicating with the lab or a genetic expert.

Possible Outcomes of Cancer Genetic Testing

Clinical Presentation of Person to be Tested Genetic Testing Result Interpretation Recommendations for Family Members
Affected Positive True positive. Disease-causing variant identified. Test confirms clinical diagnosis or clinical suspicion.
Targeted testing of first-degree family members is strongly recommended. Those with positive results are at risk for developing cancer. Those with negative results are not at increased risk.
Affected Negative The result does not rule out the diagnosis or a genetic cause of the cancer.
Testing of family members not indicated.
Affected Variant of uncertain clinical significance (VUS)
The result, at this time, is uninformative. Testing of family members not typically indicated.
Unaffected Positive Patient is at risk for developing cancer.
Targeted testing of first-degree family members is strongly recommended. Those with positive results are at risk for developing cancer. Those with negative results are not at an increased risk .
Unaffected Negative Patient is likely not at increased risk of cancer, but a genetic cause cannot be ruled out unless familial variant is known.
Testing of family members may be indicated, depending on the family history.
Unaffected Variant of uncertain  clinical significance (VUS) The result, at this time, is uninformative. Testing of family members not typically indicated.

Reviewed January 2020