CMS Pub. 100-04, ch. 28, § 80.3.1

A. Outbound COB

The outbound COB transaction is a post-adjudicative transaction. This transaction

includes the incoming claim data as well as COB data. A/B MACs (A) are required to

receive all possible data on the incoming ASC X12 837 although they do not have to

process non-Medicare data. However, the shared system must store that data in a SFR.

This repository file will be designed and maintained by the shared system. This data

must be re-associated with Medicare claim and payment data in order to create an IG

compliant outbound COB transaction using the Medicare Part A Claim/COB flat file as

input. The shared system is to use post-adjudicated Medicare data (data used from

history and reference files to adjudicate the claim) instead of data received when building

the outbound COB transaction. The shared system must retain the data in the SFR for a

minimum of six months.

The Medicare Part A Claim/COB flat file is the format to be used to re-associate all data

required to map to the COB transaction. The translator will build the outbound COB

transaction from the Medicare Part A Claim/COB flat file.

The shared system maintainer must accommodate the COB transaction.

A/B MACs (A) shall refer to §70.6 through 70.6.5 for additional guidance concerning the

national COBA crossover process.

B. Summary of Process

The following summarizes all A/B MAC (A) steps from receipt of the incoming claim to

creation of the outbound COB:

A/B MAC (A)’s translator/edit process performs syntax edits, IG edits, and

Medicare edits and maps incoming claim data to the Medicare Part A Claim/COB

flat file;

Medicare data on the Medicare Part A Claim/COB flat file is mapped to the core

system by the shared system.

NOTE: No changes are being made to core system data fields or field sizes;

Non-Medicare data (and Medicare data elements where field sizes are in excess of

the core system) are written to the SFR by the A/B MAC (A)’s shared system;

and

Adjudicated data is combined with SFR data to create the outbound COB

transaction.