AR Follow-Up and Recovery Services

Accounts Receivable Follow-Up for Medical Practices, From the First Status Check to Aged Claim Recovery

A2Z’s AR follow-up services work your unpaid claims from the first status check through aged claim recovery. Most AR does not age because payers refuse to pay. It ages because claims are rejected before adjudication, denied with a fixable code, underpaid without notice, or run past a filing limit with no one watching. Our accounts receivable follow-up services are built for practices with balances past 60 days and practices that inherited a backlog from a previous biller.

What AR Follow-Up Covers, and Where Claims Stall

An AR follow-up process involves attempting to collect all unpaid claims until they are paid, corrected, appealed, or written off through a formal determination. There are three stages where claims may become stagnant and require distinct types of action.

Before adjudication, a claim is rejected for data errors and usually produces no 835, so there is nothing to post and nothing to see.
During adjudication, a claim can be pended because it is incorrect or incomplete, or suspended with a request for more information.
After adjudication, it comes back denied or underpaid.

Payment posting is used to read remittances, and denial management is utilized for handling appeals. The AR follow-up process is designed to cover the work associated with each as well as all other claims that have yet to be paid, including those that were not denied.

How We Work AR by Aging Bucket

Aging buckets decide the type of action a claim gets. Medical billing AR follow-up works each bucket differently, because a claim at 20 days and a claim at 100 days have different problems. The first bucket contains jobs to verify acceptance of claims, as well as jobs to clear up rejected claims. We prioritize the work in the bucket based upon both the deadline risk and the balance of each claim.

In the second, silence is the problem. In the third, denied and underpaid claims turn up unworked. After 90 days, you are dealing with aged AR, or aged accounts receivable, and those claims need escalation and a filing limit check. After 120 days, a claim goes to a recovery review. This method sits inside our wider revenue cycle management services.

Bucket	What Usually Explains It	Primary Action
0 to 30 days	Claim in process, or rejected before adjudication	Confirm acceptance and status electronically. Clear rejections as they appear.
31 to 60 days	No response, pended for information, or not received	Status check by 276/277 or payer portal. If the payer has no record, resubmit with proof of filing.
61 to 90 days	Denied or underpaid and not yet worked	Work by remittance code. Correct, or hand off to appeals. Confirm secondary and tertiary claims are billed.
91 to 120 days	Escalation territory	Payer provider relations contact. Check filing limit exposure against the payer contract. Prioritize by balance and recoverability.
Over 120 days	Backlog	Recovery review: filing deadline audit first, then triage by cause (see the recovery block).

Checking Claim Status Before Picking Up the Phone

The claim status check begins with either an electronic 276 inquiry and 277 response, or via a payer’s website, and if those two methods fail to provide the answer to your question regarding the status of your claim, then you can call them on the telephone.

The 276 and 277 are the HIPAA claim status inquiry and response transactions (ASC X12, version 5010). These two electronic methods allow a billing team to find out from a payer what stage their claim has reached. A 277 can tell you whether your claim was accepted or rejected before adjudication; if your claim was pended due to an error or missing information; or if your claim was suspended while the payer requests additional details.

Under the CAQH CORE 250 Claim Status Rule, a real-time 277 response will be returned within 20 seconds. If you submit a batch of 276 inquiries by 9:00 PM Eastern Standard Time (EST) on a business day, then your 277 batch response will be available to you by 7:00 AM EST the following business day. Your 999 acknowledgment will be provided to you within one hour after submission. Plans are required to create a companion guide.

Faster status checks mean more claims covered in a day. A claim the payer has no record of starts the proof of filing step.

Reading the Remittance: Codes That Decide the Next Step

The combination of CARC and RARC on the remittance determines if the subsequent action will be a correction, an appeal, a COB (coordination of benefits) repair, or nothing.

CARCs provide an explanation of the reason for the reduction in payment, and RARCs expand on the reason for the reduction. Both types of codes are used in both 835s and on paper remittances. Usually, when a claim is rejected prior to being adjudicated, there will be no 835 generated for the claim; therefore, the claim will not appear in this table. If there is an error in the submission of a claim, the provider can correct the error. If there is a disagreement with the decision made by the payer regarding the amount paid, the provider can appeal the decision. Submitting a correctable claim to appeals will take weeks.

Correct and resubmit (CARC 4, 16, 18, 22, 252). Therefore, the resolution will either be to correct the error on the claim form itself, submit any required documentation that was missing from the initial submission, or verify if the original claim has been paid.
Hand off to appeals or authorization (CARC 15, 50, 97, 197). Clinical appeals go to denial management, and missing authorizations go to our prior authorization services.

Code	What It Means	Typical AR Action
CARC 4	Procedure code inconsistent with the modifier, or a required modifier is missing.	Check the claim against the note, correct the modifier, and resubmit as a corrected claim.
CARC 15	Authorization number missing, invalid, or does not apply to the billed service or provider.	Check the authorization record, request correction or a retro authorization where the payer allows, then reprocess.
CARC 16	Claim lacks information or has a submission or billing error	Find the missing element named in the RARC, correct and resubmit. This is a correction, not an appeal.
CARC 18	Exact duplicate claim or service	Confirm whether the original was paid or is pending. Do not rebill. If the payer has no record of the original, start the proof of filing step.
CARC 22	May be covered by another payer per coordination of benefits	Verify coverage order with the patient and payer, update COB, bill the correct primary.
CARC 27	Expenses incurred after coverage terminated	Re-verify eligibility on the date of service, look for other coverage, and route to patient billing only if none exists.
CARC 29	The time limit for filing has expired	Pull proof of timely filing (clearinghouse acceptance report, earlier payer rejection or denial with dates) and submit it. If none exists, recommend a write-off for the practice to approve.
CARC 45	Charge exceeds fee schedule or contracted amount	Usually the contractual write-off. Compare the allowed amount to the contract rate before writing it off.
CARC 50	Not deemed a medical necessity by the payer	Clinical review and appeal with documentation. Hand off to Denial Management.
CARC 97	Benefit included in the payment for another service already adjudicated	Review the bundling edit and modifiers, then correct or appeal.
CARC 109	Claim or service not covered by this payer	Identify the correct payer through eligibility, bill them, and check the filing limit against that payer.
CARC 197	Precertification, authorization or notification absent	Check whether an authorization existed, request a retro authorization, and hand off to the Prior Authorization process.
CARC 252	Attachment or other documentation required	Send the documents named in the RARC and track receipt.

Timely Filing, Prompt Pay and the Clock on Every Claim

Every claim runs on two clocks, the filing limit and the payer’s payment timeline, and both come from the payer’s rules or contract.

Medicare will not process an electronic claim that is clean before 14 days following the date of submission, nor will Medicare process a paper claim that is clean before 29 days following the date of submission. Interest will accrue beginning with day 31 following the date of submission if a clean claim has not been processed. This means that Medicare fee-for-service AR operates under a different timeline than commercial insurance companies. Also, a clean claim that is unprocessed beyond day 30 should prompt you to inquire about its status. The filing deadlines and processing timelines for Medicaid and commercial insurance vary based upon state and individual contracts; therefore, we review the specific terms of each insurer. State prompt pay laws set payer deadlines in many states, and our New York and Pennsylvania pages cover those states.

When a payer denies with CARC 29, the answer is proof of timely filing: the clearinghouse acceptance report, the payer acknowledgment, or any dated rejection or earlier denial. If none exists, we recommend a write-off for you to approve.

Underpayments: Paid Claims That Still Owe the Practice Money

A paid claim gets no follow-up in most workflows, and that is where underpayment hides. Insurance underpayment recovery starts by treating a paid claim as one that may still need work.

The allowed amount on the remittance does not match the contracted rate, or a payer-initiated reduction is applied with no explanation. Payment posting flags the difference. AR follow-up recovers it by disputing with the contract rate and the claim detail, and escalating through provider relations when the first dispute does not resolve it.

AR Recovery: Cleaning Up Aged Claims and Inherited Backlogs

AR recovery is a project for the balance over 120 days, whether it was inherited from a previous biller or built up in-house. Our AR recovery services work aged accounts receivable in four steps.

Audit filing deadlines per payer.

Claims that can still be filed are worked first.

Segment by cause.

Each claim is sorted as correctable, appealable, underpaid, wrong payer, patient responsibility, or not recoverable.

Work by recoverability and balance.

The claims most likely to pay and the largest balances come first.

Deliver a write-off recommendation list.

Each claim comes with a reason, and you approve every write-off.

A claim is only worked as long as expected recovery exceeds the cost of working it. Patient responsibility balances move to patient billing. We do not promise a recovery percentage. This is medical AR recovery done as a project, and the same AR cleanup services can then feed into ongoing follow-up on aged AR as it appears.

What You Receive: AR Reporting

Medical billing accounts receivable management only works if you can see what is happening to each claim.

Aging by payer and bucket.

Days in AR, with the definition stated, because definitions vary.

Top adjustment and denial reasons by payer.

A timely filing risk list.

A log of claims reworked.

An underpayment log.

These reports are reviewed with you on a regular call.

Outsourcing AR Follow-Up to A2Z

A2Z Follows Up on Unpaid Claims and Contacts Payers, While You Make All Decisions Related to Your Practice.

With outsourcing your accounts receivable follow-up, you turn over claims work, contacts with payers, and reporting. You retain the ability to approve write-offs and provide documentation for appeals. A2Z works inside your existing system with role-based access under a business associate agreement, so no migration is needed. Onboarding takes 2 to 4 weeks depending on your EHR and payer mix.

AR Follow-Up by Specialty

Mental health

Physical therapy

Internal medicine

Family practice

Get Started with a Dedicated AR Follow-Up Team

Send us your aging report, and we will show you what is recoverable.

Get a Free Billing Review

Why Practices Choose A2Z for AR Follow-Up

Choose an AR follow-up partner by what it does with a claim in the first review.

A code-based diagnosis for every aged claim

Each claim is read against its CARC and RARC before anyone works it.

Filing deadlines tracked

Every claim has its filing limit on file by payer.

Proof of filing kept.

Clearinghouse reports and payer acknowledgments stay with the claim.

Underpaid claims followed up.

Paid claims are checked against contract rates as well as denied ones.

Transparent reporting

You see what was worked, what is at risk, and what was written off.

Frequently Asked Questions (FAQs)

What is the difference between a rejected claim and a denied claim?

A rejected claim is stopped before adjudication for data errors and usually produces no 835. A denied claim has been adjudicated and is listed on the remittance with a CARC. Because there are no items sent to you when a claim is rejected, these claims age silently. Therefore, your AR follow-up will check for both acceptance and status.

What is the difference between AR follow-up and denial management?

AR follow-up works on every unpaid claim, including claims that were never denied. Denial management handles denied claims through root cause analysis and appeal. The handoff happens when a claim needs clinical documentation or a formal appeal, such as a CARC 50 medical necessity denial, which moves to denial management.

How long should a claim sit unpaid before you follow up?

It depends on the payer. Medicare does not pay a clean electronic claim before day 14 or a clean paper claim before day 29, and interest begins on day 31. A clean Medicare claim still unpaid after day 30 is a status check. Commercial payers follow their contracts, so their timelines come from their own terms.

Can claim status be checked electronically?

Yes. The 276/277 transaction lets a billing team ask a payer electronically where a claim stands. Under CAQH CORE 250, a real-time 277 response is due within 20 seconds. Payers must publish companion guides that explain how they support the transaction. When electronic status cannot answer, the payer portal or a phone call is the fallback.

What happens if the timely filing limit has passed?

A CARC 29 denial can sometimes be answered with proof of timely filing, such as a clearinghouse acceptance report or an earlier payer rejection or denial with dates. Without proof, the practice decides whether to write the claim off, and we recommend that decision with the reasons. We do not promise recovery on a claim past its limit.

What does AR recovery cover that regular follow-up does not?

AR recovery covers aged balances over 120 days, backlogs inherited from a previous biller, a filing deadline audit, triage by cause, and a write-off recommendation list. Regular follow-up works on claims as they age.

Can you take over AR from our previous billing company?

Yes. We start with your aging report and claim history, audit filing deadlines first so the claims that can still be filed are worked first, and then triage the rest by cause.

Do you work AR inside our existing system?

Yes. We work inside your existing system with role-based access under a business associate agreement, so no migration is needed. Onboarding takes 2 to 4 weeks depending on your EHR and payer mix. Your team keeps its own access, you approve write-offs, and you supply records for appeals when we request them.