Cal. WIC § 10022

(a) Each publicly funded health care program, as defined in paragraph (1) of subdivision (b) of Section 10020, that furnishes or pays for health care items or services under this division to a person having private health care coverage shall be entitled to be subrogated to the rights that person has against the carrier of the coverage to the extent of the health care items provided or services rendered.

(b) An entity providing private health care coverage, as defined in paragraph (2) of subdivision (b) of Section 10020, shall do all of the following:

(1) Accept the state’s right of recovery and the assignment to the state of any right of an individual or other entity to payment from the party for an item or service for which payment has been made under the state plan, waivers granted in accordance with Section 1315 or 1396n of Title 42 of the United States Code, or through a Medi-Cal managed care plan, as defined in subdivision (j) of Section 14184.101.

(2) Respond to an inquiry by the state or a provider, as defined in subdivision (o) of Section 14043.1, including a billing agent or a billing agent of the provider, as defined in subdivision (a) of Section 14040.1, or a Medi-Cal managed care plan, as defined in subdivision (j) of Section 14184.101, regarding a claim for payment for a health care item or service that is submitted not later than three years after the date of the provision of that health care item or service.

(3) Agree not to deny a claim submitted by the state, a provider as defined in paragraph (2), or a Medi-Cal managed care plan, as defined in subdivision (j) of Section 14184.101, solely on the basis of the date of submission of the claim, the type or format of the claim form, or a failure to present proper documentation at the point-of-sale that is the basis of the claim, or in the case of a responsible third party, a failure to obtain a prior authorization for the item or service for which the claim is being submitted if both of the following occur:

(A) The claim is submitted by the state, a provider as defined in paragraph (2), or a Medi-Cal managed care plan, as defined in subdivision (j) of Section 14184.101, within the three-year period beginning on the date on which the item or service was furnished.

(B) An action by the state, a provider as defined in paragraph (2), or a Medi-Cal managed care plan, as defined in subdivision (j) of Section 14184.101, to enforce its rights with respect to that claim is commenced within six years of the state’s or provider’s submission of the claim.

(4) Request a refund of a claim paid in error no later than three years from the date the payment was made to the State Department of Health Care Services. The State Department of Health Care Services shall not refund a claim paid in error if the request for a refund is more than three years from the date the payment was made to the State Department of Health Care Services.

(5) Respond to a request for payment by the state, a provider as defined in paragraph (2), or a Medi-Cal managed care plan, as defined in paragraph (2), within 60 days by providing one of the following:

(A) Payment on the claim.

(B) A written request for additional information necessary to process the claim.

(C) A written explanation for the denial of the claim.