No, your plan may not impose the preexisting condition exclusion because prior to the employee’s enrollment date, she was not diagnosed with breast cancer.

Preexisting condition rules. Under HIPAA, the ability of most group health plans or health insurers, including HMOs, to exclude an individual from health coverage due to a preexisting condition is restricted.

A preexisting condition exclusion is permissible if it relates to a physical or mental condition for which medical advice, diagnosis, care, or treatment was recommended or received within six months before the enrollment date in the new plan. Conditions not diagnosed or treated during that six-month period prior to the enrollment date are not subject to any coverage exclusion. Genetic information is not considered a condition.

Definition of genetic information. The HIPAA regulations define genetic information as information about genes, gene products, and inherited characteristics that may derive from the individual or a family member. This includes information regarding carrier status and information derived from laboratory tests that identify mutations in specific genes or chromosomes, physical medical examinations, family histories, and direct analysis of genes or chromosomes.