CARC 252: Build a Documentation Response the Payer Can Match to the Claim

A CARC 252 adjustment needs a specific document response. Before uploading records or sending another claim, determine what the payer is missing and how the response must be linked to the original service.

X12 lists CARC 252 as active: an attachment or other documentation is needed to adjudicate the claim or service. Its instructions require at least one accompanying remark code. Read that remark and any separate request together. The reason code alone does not identify the required records or submission route.

Open one accountable work item

Capture the payer, claim identifier, service dates, affected lines, remark codes, request reference, deadline, and destination. Assign one owner to coordinate records and confirm receipt. Include a backup owner when the deadline falls during an absence.

Check the claim’s current status. A request for records, a pending medical review, and a final denial can require different actions. Do not assume every CARC 252 account follows the same Medicare review process.

Use the deadline for the actual request

For Medicare additional documentation requests, CMS distinguishes contractor and review type. MAC prepayment reviews allow 45 calendar days; MAC, SMRC, and RAC post-payment reviews also allow 45 days. UPIC requests generally allow 30 days. Read the notice and applicable instructions rather than setting one deadline for every payer.

CMS encourages working with the designated MAC if more time is needed. Acceptance of a late response for good cause is discretionary. Escalate missing records early instead of assuming an extension will be granted.

Assemble a claim-specific packet

Turn the request into a checklist. Identify each requested record, its service period, source, and location in the response. Verify legibility, patient identity, relevant signatures, and completeness before submission.

CMS recommends putting the ADR letter first so the response can be matched to the patient and claim. CGS’s Part A instructions recommend relevant supporting records rather than an indiscriminate full-chart upload, and clearly separated documentation for each claim. Follow the receiving contractor’s format and channel requirements.

For a specialty procedure, the packet might require an order, procedure report, and related encounter documentation. Let the actual request and applicable policy determine the contents. Do not create missing clinical facts to complete the checklist.

Confirm receipt and continue tracking

Retain the submitted packet, transmission confirmation, destination, and date in the approved secure system. Where the portal distinguishes receipt from acceptance, check both. A successful upload is not evidence that the payer approved the service.

Noridian’s DME review guidance warns against replacement or duplicate claims while an ADR is pending. Use the designated documentation channel and check status before sending an unchanged claim again. If a denial has already issued, follow the applicable correction, reopening, or appeal instructions and preserve that separate deadline.

Reduce repeat requests

Review a monthly sample for missing documents, unmatched submissions, incomplete packets, and missed deadlines. Separate records that existed but were omitted from records that were never completed. Each problem needs a different owner and preventive check.

Sources

X12: Claim Adjustment Reason Codes, CARC 252

https://x12.org/codes/claim-adjustment-reason-codes

CMS: Additional Documentation Request

https://www.cms.gov/data-research/monitoring-programs/medicare-fee-service-compliance-programs/medical-review-education/additional-documentation-request

CGS: ADR Process, What to Send

https://www.cgsmedicare.com/parta/mr/articles/adr-what-to-send.html

Noridian: Claim Review Preparation, JD DME

https://med.noridianmedicare.com/web/jddme/cert-reviews/mr/claim-review-preparation

How Syntra can help

Syntra reviews charts and claims together to identify documentation gaps before submission. Use a targeted audit to find recurring missing evidence and turn validated findings into practice-specific pre-bill checks. Keep records requests, submission confirmation, and response deadlines with your billing and records teams, supported by clear handoffs for clinician clarification.