California Code, Health and Safety Code - HSC § 1373.14

Except for a preexisting condition, any health care service plan, except a specialized health care service plan, which provides coverage on a group or individual basis for long-term care facility services or home-based care shall not exclude persons covered by the plan from receiving these benefits, if they are diagnosed as having any significant destruction of brain tissue with resultant loss of brain function, including, but not limited to, progressive, degenerative, and dementing illnesses, including, but not limited to, Alzheimer's disease, from the coverage offered for long-term care facility services or home-based care.

For purposes of this section, where a particular disease can be determined only with an autopsy, “diagnosed” means clinical diagnosis not dependent on pathological confirmation, but employing nationally accepted criteria.