N706 Remark Code: Missing Documentation, What to Send

The N706 remark code means documentation the payer needs for the service is missing, so it adjusted the line instead of paying it as billed. It supplements a reason code such as CARC 252, which says an attachment or other documentation is required to adjudicate the claim. On Medicare, CMS uses CO-252 with N706 when a physician bills modifier 22 without supporting documentation, and a Medicare contractor says such claims process under the normal fee schedule.

What is the N706 remark code? N706 is a Remittance Advice Remark Code (RARC) meaning "Missing documentation," added to a claim adjustment reason code, such as CARC 252, to show the payer adjusted the service because required supporting documents were not received.

Undeny's Take

N706 tells you the category of the problem, not the document. "Missing documentation" can mean an operative report, a signed plan of care, an order or a form the policy requires, so your first job is to name the exact document before you send anything. The second job is to send it in a way the payer can match to the claim. A Medicare contractor's own guidance on modifier 22 is a good model: use the claim's paperwork (PWK) segment to flag that documentation is coming, attach the payer's cover sheet, and include a specific statement rather than "see report." Fewer but better pages beat a stack of unlabeled records.

What N706 Means and Which CARCs Carry It

The X12 description is simply "Missing documentation." Many billers call it the N706 denial code, and you will also see it written as remark code N706. The Medicare Claims Processing Manual (Pub. 100-04, Chapter 22) explains that remark codes "further explain an adjustment," so read N706 with the reason code beside it.

CARC 252. X12 describes 252 as "An attachment/other documentation is required to adjudicate this claim/service," and requires a remark code with it. CARC 16, by contrast, carries the usage note "Do not use this code for claims attachment(s)/other documentation," which is why documentation gaps point to 252 rather than 16.
Medicare modifier 22 (Chapter 12, section 40.4). "When a physician submits a claim with modifier '-22' but does not provide additional documentation," CMS lists Group Code CO, CARC 252 and RARC N706 as the message for the payment amount, so the line reads CO-252 N706.
Other pairings exist. A question submitted to X12 (RFI 2578) describes a payer sending CARC 204 with N706 and argues CARC 226 fit better. X12 replied that commenting on a payer's code usage is outside its purview, so expect some variation between payers.

Why Payers Flag Missing Documentation

The service or modifier carries a documentation requirement. WPS, a Medicare contractor, says modifier 22 claims need "An operative report" and "A separate statement indicating how the service differs from the usual," and that without them the claim "will process based on normal Medicare guidelines and fee schedule."
Documentation was sent but not matched to the claim. WPS ties electronic modifier 22 claims to documents through the PWK segment and its fax, mail or esMD cover sheet.
The documents did not cover what the policy asks for. A record that omits the specific element the payer needs can be treated as missing.

How to Respond to N706

Read the CARC and group code with N706 to learn whether the line was denied, reduced or returned.
Find the payer's documentation requirement for the service or modifier, such as a policy, LCD or contractor fact sheet.
Gather exactly what it lists, signed and dated for the date of service, and add a short cover statement tying the documents to the claim.
Send it through the payer's channel, such as PWK with the payer's cover sheet, the portal, or a response to the development letter, and keep proof of delivery.
If you had already sent complete documentation, request a reopening or appeal with your proof of submission. The appeal generator can draft it.

N706 Compared With M127, CO-252, CO-16 and CO-50

CO-252 is the reason code CMS pairs with N706. M127 is narrower, a missing patient medical record, and is the remark CMS uses with CO-50 when Medicare documentation requests go unanswered. CO-16 covers claims that lack information or have billing errors, but X12 says not to use it for attachments. CO-50 is a medical necessity denial. When the missing document is a justification letter, see the letter of medical necessity template.

Frequently Asked Questions

What documentation does N706 want?

N706 does not name the document, so the answer comes from the payer's policy for the service. For Medicare modifier 22, a Medicare contractor lists an operative report and a separate statement explaining how the service differed from the usual. Other services and payers have their own lists.

What is the difference between N706 and M127?

N706 is general: some required documentation is missing. M127 is specific: the patient's medical record for the service is missing, and CMS pairs it with CO-50 when a documentation request goes unanswered. Both are fixed by sending the right records.

Why is N706 paired with CARC 252 instead of CARC 16?

X12's usage note for CARC 16 says not to use it for claim attachments or other documentation. CARC 252 exists for exactly that situation and requires a remark code, so N706 is a natural partner that tells you documentation is the gap.

Can I send documentation with the claim to prevent N706?

Where the payer supports it, yes. A Medicare contractor describes using the PWK segment of the electronic claim to signal that documentation is coming, then sending it with the payer's cover sheet at the time of claim submission. Check each payer's attachment process before relying on it.

Informational only, not legal, medical, or billing advice. Always verify against your current payer contract and policy.

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