CMS Pub. 100-05, ch. 5, § 40.1

Where the claimant indicates Medicare is the primary payer, the A/B MACs (Part A), A/B MACs

(Part B), and A/B MACs (Part HHH) (collectively referred to as A/B MACs) and the DME MACs

assume, in the absence of evidence to the contrary, that the claimant has correctly determined that

there is no primary GHP coverage and processes the claim. It pays primary Medicare benefits only if

the services were not rendered during a coordination period, or if the GHP denies a claim because

the beneficiary is not entitled to benefits under the plan, or benefits under the plan are exhausted for

the particular services, or the services are not covered by the GHP, and the beneficiary is not

appealing the GHP denial. The A/B MAC and the DME MAC does not pay primary benefits if there

is reason to believe that the GHP covers the services. If the A/B MAC and the DME MAC pays

primary Medicare benefits and later learns that the beneficiary is appealing the GHP denial, it treats

the payment as a conditional primary payment. Any necessary recovery actions will later be

initiated by CMS’s Commercial Repayment Center.

If the A/B MACs (Part A) believes that a GHP may be the primary payer, it returns the bill to the

provider requesting the provider to ascertain whether primary GHP benefits are payable, and if so, to

bill for primary benefits. The A/B MAC (Part A) should instruct the provider that if a GHP has

denied its claim for primary benefits, the provider must annotate the claim with the reason for the

denial and enter occurrence code 24 and the date of denial. No attachment is needed.

If the A/B MACs (Part B) believes that a GHP may be the primary payer, the A/B MACs (Part B)

will return the bill to the physician or other supplier requesting the provider to ascertain whether

primary GHP benefits are payable, and if so, to bill for primary benefits. The A/B MACs (Part B)

shall instruct the physician or other supplier on the remittance advice that if a GHP has denied its

claim for primary benefits, the provider must annotate the claim with the reason for the denial in the

CARC segment. No attachment is needed.

When a claim is received from a member of a religious order who has taken a vow of poverty, whose

order filed an election under §3121(r) of the IRC, and who does not have group health coverage from

employment outside the order, the A/B MAC processes the claim as a primary Medicare claim.

A GHP's decision to pay or deny a claim because it determines that the services are or are not

medically necessary is not binding on Medicare. The A/B MACs and DME MACs evaluate claims

under existing guidelines to assure that Medicare covers the services, regardless of the GHP decision.