CMS Pub. 100-04, ch. 22, § 40.2

The ASC X12 835 IG contains specific data requirements, which must be met to build a

HIPAA compliant ERA. A claim could be received on paper that lacks data or has data

that does not meet the data attributes or length requirements for preparation of a HIPAA-compliant ERA. If not rejected as a result of standard or IG level editing, a MAC must

either send an SPR advice or a “gap filled” ERA to avoid noncompliance with HIPAA.

For example, if a procedure code is sent with only four characters and the code set

specified in the IG includes five character codes in the data element, and the code is not

rejected by the front end edits, the claim would be denied due to the invalid procedure

code. Preparation of an ERA with too few characters though would not comply with the

IG requirements. The noncompliant ERA could be rejected by the receiver.

The shared system maintainers, working in conjunction with their MACs, must decide

whether to generate an SPR, which is not covered by HIPAA, or to “gap fill” in this

situation, depending on system capability and cost. Except in some very rare situations,

“gap filling” would be expected to be the preferred solution. Shared System Maintainers

must follow CMS gap-filling instruction. The MAC must notify the trading partners, if

and when their files are affected, as to when and why gap-filling characters will appear in

an ASC X12 835.