Welf. & Inst. Code, § 14023.7

Any provider of service seeking payment for health care services for a person eligible for these services under this chapter shall first seek to obtain payment from any private or public health insurance coverage to which the person is entitled, where the provider is aware of this coverage and to the extent the coverage extends to these services, prior to submitting a claim to the department for the payment of any unpaid balance for these services. In the event that a claim submitted to a private or public health insurer has not been paid within 90 days of billing by the provider, a claim may be submitted to the department.