Washington Revised Code Title 48. Insurance § 48.43.605. Overpayment recovery--Health care provider

(1) Except in the case of fraud, or as provided in subsection (2) of this section, a health care provider may not: (a) Request additional payment from a carrier to satisfy a claim unless he or she does so in writing to the carrier within twenty-four months after the date that the claim was denied or payment intended to satisfy the claim was made; or (b) request that the additional payment be made any sooner than six months after receipt of the request. Any such request must specify why the provider believes the carrier owes the additional payment.

(2) A health care provider may not, if doing so for reasons related to coordination of benefits with another carrier or entity responsible for payment of a claim: (a) Request additional payment from a carrier to satisfy a claim unless he or she does so in writing to the carrier within thirty months after the date the claim was denied or payment intended to satisfy the claim was made; or (b) request that the additional payment be made any sooner than six months after receipt of the request. Any such request must specify why the provider believes the carrier owes the additional payment, and include the name and mailing address of any entity that has disclaimed responsibility for payment of the claim.

(3) If a contract between a carrier and a health care provider conflicts with this section, this section shall prevail. However, nothing in this section prohibits a carrier from choosing at any time to make additional payments to a provider to satisfy a claim.

(4) This section does not apply to claims for health care services provided through dental only health carriers, health care services provided under Title XVIII (medicare) of the social security act,  1 or medicare supplemental plans regulated under chapter 48.66 RCW.