Section 800.502 - MSP issuer internal claims and appeals(a)Processes. MSP issuers must comply with the internal claims and appeals processes applicable to group health plans and health insurance issuers under 45 CFR 147.136(b) .(b)Timeframes and notice of determination. An MSP issuer must provide written notice to an enrollee of its determination on a claim brought under paragraph (a) of this section according to the timeframes and notification rules under 45 CFR 147.136(b) and (e) , including the timeframes for urgent claims. If the MSP issuer denies a claim (or a portion of the claim), the enrollee may appeal the adverse benefit determination to the MSP issuer in accordance with 45 CFR 147.136(b) .