CARC 16
Something is missing or wrong on the claim
The most common and least specific denial there is. The payer needs more before it can adjudicate.
Why you actually get this
- A required field is absent or malformed.
- Supporting documentation the payer expected was not attached.
- An identifier — provider, member, referring physician — is missing or invalid.
How to check whether it’s correct
- 01Read the accompanying remark code. CARC 16 almost never travels alone, and the RARC is where the actual reason lives.
- 02Check the claim for missing identifiers before assuming it is a documentation issue.
Usually worth appealing
Nearly always correctable, but only once you know what is actually missing — and that is in the remark code rather than in CARC 16 itself. Working these without reading the RARC is guesswork, and it is the single most common way billing teams waste time.
Often arrives with
Seeing a lot of these?
A single denial is a claim to work. A pattern of the same denial is a process to fix, and the two need completely different responses. A free panel reads ninety days of your claims data and shows which codes actually recur for you.
Claim Adjustment Reason Codes are maintained by X12 as External Code List 139. The official description of this code is theirs and is not reproduced here. Check the authoritative list for current wording and status.