US · guidance
CMS Pub. 100-05, ch. 5, § 30
Develop Claims for Medicare Secondary Benefits
When Medicare is indicated as primary payer on a claim, assume, in the absence of evidence to the
contrary, that the provider has correctly determined that there is no other primary coverage and
process the claim accordingly. There are instances in which further development is necessary, as
discussed in §30.2.
Under the COB contract, the MSP Contractor is responsible for developing whether there is a payer
primary to Medicare. The A/B Medicare Administrative Contractors (MACs) (Part A), A/B MACs
(Part B), or A/B MACs (Part HHH) (collectively referred to as A/B MACs) and Durable Medical
Equipment MACs (DME MACs) supplies the MSP Contractor information via ECRS or by
telephone or fax, depending on circumstances. The A/B MAC and DME MAC obtains the MSP data
needed to process claims via CWF, which the MSP Contractor updates with the results of its
investigations. There is some minimal provision for the A/B MAC and DME MAC to update the
MSP auxiliary file on CWF with MSP information. See §10.1, above.
History
(Rev. 11550; Issued: 08-12-22; Effective: 10-13-22; Implementation:10-13-22)
Provenance
- Source
- cms.gov
- Retrieved
- 2026-08-25
- Edition
- iom-2026-08-25
- Content hash
7d780533502734ec2882fa7a1d0bc94be37937be54d0c3f594f831496f19caea
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