For a physician, hospital, or clinic, submitting a claim is only the beginning of the reimbursement process. A claim can leave the practice correctly, reach the payer successfully, and still remain unpaid because of an eligibility problem, missing authorization, coding inconsistency, documentation request, coordination-of-benefits issue, or payer processing delay.
That is where AR follow-up in medical billing becomes essential.
Accounts receivable follow-up is the structured process of tracking unpaid, underpaid, denied, rejected, and delayed claims until the correct financial resolution is reached. Done properly, it does more than recover old balances. It helps healthcare organizations identify patterns that are quietly slowing cash flow in the first place.
For doctors, physicians, hospitals, and clinics, an effective AR process can mean fewer claims aging beyond filing or appeal deadlines, fewer preventable write-offs, better visibility into payer behavior, and more predictable reimbursement.
This guide explains how AR follow-up works, which claims deserve attention first, how CPT, HCPCS, ICD-10-CM, modifiers, denial codes, and remark codes affect outstanding claims, and how healthcare organizations can build a more disciplined strategy for getting paid.
What Is AR Follow-Up in Medical Billing?
AR follow-up in medical billing refers to the work performed after a healthcare claim has been submitted but has not reached the expected financial outcome.
That outcome may be:
- Full payer reimbursement
- Contractually correct partial reimbursement
- Legitimate patient responsibility
- A justified contractual adjustment
- An approved appeal or corrected claim
- A properly documented non-covered balance
- A valid write-off after all appropriate recovery options have been exhausted
An outstanding AR balance should therefore never be viewed simply as “money the payer has not paid.”
Every balance has a reason.
A strong AR process identifies that reason quickly and determines the correct next action.
For example, a claim may remain open because the payer:
- Never received it
- Rejected it before adjudication
- Denied it for missing information
- Requested medical records
- Applied the wrong contractual rate
- Bundled one service into another
- Determined that authorization was missing
- Found another insurer responsible
- Applied deductible, coinsurance, or copayment
- Questioned medical necessity
- Considered the service a duplicate
- Applied an NCCI edit
- Processed the claim under an incorrect provider record
Effective AR follow-up separates these situations instead of treating every unpaid claim the same way.
Why AR Follow-Up Matters to Physicians, Hospitals, and Clinics
A growing accounts receivable balance does not always mean that more money is coming.
Sometimes it means exactly the opposite.
As claims move into older aging categories, they may approach payer filing limits, reconsideration deadlines, appeal deadlines, medical-record submission deadlines, or internal collection limits. Some claims also become progressively more difficult to research because authorizations, referrals, documentation, eligibility data, and payer correspondence become harder to reconstruct.
Medicare fee-for-service claims normally must be filed within twelve months from the date services were provided, except in a special cases. CMS says that if a Medicare fee-, for-service claim is filed after the required twelve-month period it may be rejected.
Commercial insurance and Medicaid plans can use very different filing and appeal requirements.
That is why AR management should be based on both claim age and deadline risk, not simply the outstanding dollar amount.
Good follow-up protects:
Cash flow.
Claims are addressed before they become stale.
Revenue integrity.
Underpayments and inappropriate adjustments are identified instead of automatically accepted.
Operational efficiency.
Recurring problems can be traced back to registration, authorization, documentation, coding, charge capture, credentialing, or claim submission.
Provider time.
Physicians are contacted for clarification only when documentation or clinical information is actually necessary.
Patient experience.
Patients are less likely to receive premature or incorrect statements for balances that should still be resolved with the payer.
Understanding the AR Aging Report
The AR aging report is one of the most important tools in revenue-cycle management.
Outstanding claims are commonly grouped into aging ranges such as:
| Aging Range | Typical Priority |
|---|---|
| 0–30 days | Monitor claim acceptance and normal payer processing |
| 31–60 days | Investigate delayed or unresolved claims |
| 61–90 days | Escalate unresolved payer issues and denials |
| 91–120 days | High-priority recovery and deadline review |
| More than 120 days | Immediate action based on recoverability and filing/appeal limits |
These ranges should not become rigid rules.
A $25,000 hospital claim that has been outstanding for 32 days may deserve more attention than a $40 copayment balance that is 95 days old.
Likewise, a claim approaching a payer’s appeal deadline should be prioritized even if the balance is comparatively small.
A more useful AR priority model considers:
Dollar value + claim age + filing deadline + denial type + probability of recovery.
The AR Follow-Up Process From Claim Submission to Payment
A disciplined workflow prevents staff from repeatedly “checking status” without actually moving claims closer to resolution.
1. Confirm That the Claim Was Accepted
The first question should be simple:
Did the payer actually receive an adjudicable claim?
A clearinghouse acceptance does not always mean that the payer accepted the claim for processing.
Verify:
- Clearinghouse status
- Payer acknowledgement
- Claim control number
- Date received
- Rejection messages
- Current adjudication status
A rejected claim is fundamentally different from a denied claim.
A rejection generally occurs before adjudication because the claim cannot enter the payer’s processing system.
A denial usually occurs after the payer has received and adjudicated the claim.
This distinction determines whether the practice should correct and resubmit the original claim, submit a corrected claim, or begin an appeal or reconsideration process.
2. Identify the Exact Reason the Balance Is Outstanding
Avoid relying on vague statuses such as:
“Denied.”
“Pending.”
“Under review.”
“Not paid.”
The AR record should explain why.
Whenever possible, document:
- Claim number
- Date of service
- Billed amount
- Allowed amount
- Paid amount
- Adjustment amount
- Patient responsibility
- CARC
- RARC
- Payer representative or portal reference
- Call/reference number
- Documentation requested
- Appeal deadline
- Next action
- Follow-up date
This turns the AR account into an actionable record rather than a collection of payer notes.
Understanding CARCs and RARCs in AR Follow-Up
After Medicare processes a claim, adjudication information appears on the Electronic Remittance Advice or Standard Paper Remittance.
CMS explains that claim or service adjustments can involve three related components:
- Claim Adjustment Group Code
- Claim Adjustment Reason Code, or CARC
- Remittance Advice Remark Code, or RARC
CARCs communicate the general reason for an adjustment, while RARCs can provide additional detail.
Understanding these codes is one of the fastest ways to make AR follow-up more efficient.
Common CARC Denial and Adjustment Codes
The following codes frequently appear during AR investigation.
| CARC | General Meaning | Common AR Action |
|---|---|---|
| 1 | Deductible amount | Verify benefits and transfer legitimate responsibility |
| 2 | Coinsurance amount | Verify patient responsibility |
| 3 | Copayment amount | Confirm payer calculation |
| 4 | Procedure code inconsistent with modifier or modifier missing | Review CPT/HCPCS and modifier use |
| 11 | Diagnosis inconsistent with procedure | Review diagnosis-to-procedure relationship |
| 15 | Authorization number missing, invalid, or not applicable | Verify authorization |
| 16 | Information needed for adjudication is missing | Review accompanying RARC |
| 18 | Duplicate claim/service | Compare previous submission/payment |
| 22 | Another payer may be responsible | Investigate COB |
| 29 | Filing time limit expired | Review proof of timely filing and payer rules |
| 50 | Service considered not medically necessary | Review coverage policy and documentation |
| 96 | Non-covered charge | Review benefit and accompanying remark code |
| 97 | Payment included in another service | Investigate bundling/NCCI issue |
| 109 | Claim belongs to another payer/contractor | Verify insurance and route appropriately |
CMS’s published CARC information describes, for example, CARC 18 as a duplicate claim/service, CARC 29 as expired filing time, CARC 50 as services considered non-covered because the payer determined they were not medically necessary, CARC 97 as payment included in another service, and CARC 109 as a claim that should be sent to another payer or contractor.
The code alone, however, should not automatically determine the response.
A CARC frequently needs to be interpreted together with the group code, RARC, payer policy, submitted claim, contract, and clinical documentation.
Important Claim Adjustment Group Codes
Group codes help explain who may be financially responsible for an adjustment.
Two especially important examples are:
CO — Contractual Obligation
The adjustment is generally assigned to the provider under payer or contractual rules.
PR — Patient Responsibility
The amount may represent deductible, coinsurance, copayment, or another legitimate patient obligation.
CMS specifically notes that these group codes help assign financial responsibility.
AR staff should never automatically move every denied amount to the patient.
The denial must first be reviewed to determine whether patient billing is contractually and legally permitted.
Important RARC Examples
RARCs often provide the detail needed to understand a CARC.
Examples include:
| RARC | Meaning/AR Relevance |
|---|---|
| M15 | Separately billed services were bundled into the same procedure |
| M49 | Missing, incomplete, or invalid value code or amount |
| M50 | Missing, incomplete, or invalid revenue code |
| M51 | Missing, incomplete, or invalid procedure code |
| M52 | Missing, incomplete, or invalid date of service |
| M53 | Missing, incomplete, or invalid units/days |
| M127 | Medical record missing for the service |
X12 currently lists M15 as indicating that separately billed services or tests have been bundled because they are considered components of the same procedure, while M51 relates to missing, incomplete, or invalid procedure coding.
These codes should drive the next action.
For example:
CARC 16 + M51
may point toward a procedure-code problem.
CARC 97 + M15
may indicate a bundling issue.
Simply resubmitting the exact same claim without addressing the underlying reason will usually produce the exact same outcome.
How CPT and HCPCS Codes Affect AR Follow-Up
There is no specific CPT or HCPCS code for AR follow-up itself.
CPT and HCPCS codes describe the healthcare services, procedures, supplies, drugs, and other items being billed. AR teams review those codes when a claim is delayed or denied.
Common claim categories might contain codes such as:
| Service | Example CPT/HCPCS |
|---|---|
| Established patient office visit | 99212–99215 |
| New patient office visit | 99202–99205 |
| Hospital inpatient/observation care | Applicable 99221–99239 code families |
| Electrocardiogram | 93000 series |
| Chest radiography | 71045–71048 family |
| Joint injection/aspiration | 20610/20611 when applicable |
| Laboratory testing | Individual laboratory CPT codes |
| Drugs and biologics | Relevant HCPCS J/Q codes |
These are examples only. The correct code depends on the actual service, documentation, date of service, payer requirements, and current code set.
For calendar year 2026, CMS has published its applicable annual CPT/HCPCS code updates effective January 1, 2026.
During AR follow-up, investigate questions such as:
- Was the CPT/HCPCS code valid on the date of service?
- Was it covered under the patient’s benefit?
- Does documentation support the service reported?
- Does the ICD-10-CM code support the medical necessity requirements?
- Was the correct modifier attached?
- Did an NCCI PTP edit affect payment?
- Did an MUE affect the units submitted?
- Was prior authorization required?
- Is a payer-specific medical policy involved?
ICD-10-CM and Diagnosis Issues in AR Follow-Up
There is also no diagnosis code specifically for AR follow-up.
Instead, ICD-10-CM codes document the patient’s diagnosis, symptom, condition, or reason for the encounter.
For example, claims may involve diagnosis codes such as:
- I10 — Essential hypertension
- E11.9 — Type 2 diabetes mellitus without complications
- M25.561 — Pain in right knee
- J18.9 — Pneumonia, unspecified organism
- R10.9 — Unspecified abdominal pain
These examples should never be selected merely because a payer is more likely to reimburse them.
Diagnosis coding must accurately reflect the patient’s documented condition and follow applicable ICD-10-CM guidelines.
Important October 2026 Update
As of October 1, 2026, FY 2027 ICD-10-CM files apply to applicable patient encounters through September 30, 2027. CMS has also released the corresponding FY 2027 ICD-10-PCS files for applicable inpatient hospital reporting.
This matters in AR follow-up because a claim may deny when:
- An outdated code is submitted
- A code was not valid on the date of service
- Additional specificity was required
- Diagnosis sequencing is incorrect
- Medical necessity criteria are not satisfied
- The diagnosis conflicts with demographic information
- A payer’s LCD/NCD or commercial medical policy does not support the service
Never change an ICD-10-CM diagnosis simply to overcome a denial unless the medical record genuinely supports the correction.
Modifiers That Frequently Affect AR Denials
Modifier-related errors are a common reason claims are reduced or denied.
Several modifiers deserve particular attention during AR review.
Modifier 25
Modifier 25 may be appended to an appropriate E/M service when a significant, separately identifiable E/M service is performed on the same day as another procedure or service.
CMS specifically discusses modifier 25 in relation to separately identifiable E/M services.
The documentation must demonstrate that the E/M work is distinct from the usual work inherent in the procedure.
Modifier 59
Modifier 59 identifies certain distinct procedural circumstances.
It should not be appended automatically simply because two procedures denied as bundled.
CMS advises that modifier 59, or one of the more specific X modifiers, should be used only when the clinical circumstances and documentation support it.
XE, XS, XP and XU
CMS uses these modifiers to provide greater specificity than modifier 59 in appropriate circumstances:
XE — Separate encounter
XS — Separate structure
XP — Separate practitioner
XU — Unusual non-overlapping service
CMS notes that modifier 59 or the X modifiers should only be used when the requirements for reporting distinct services are actually met.
Other Modifiers Commonly Reviewed in AR
Depending on specialty and payer rules, AR investigation may also involve:
24 — Unrelated E/M service during a postoperative period
26 — Professional component
TC — Technical component
50 — Bilateral procedure when appropriate
RT/LT — Right or left side
76 — Repeat procedure by the same physician or qualified professional
77 — Repeat procedure by another physician or qualified professional
91 — Repeat clinical diagnostic laboratory test when applicable
CMS identifies several global surgery, anatomical, and other modifiers that can affect NCCI PTP edit processing, including 24, 25, 57, 58, 78, 79, 59, 91, XE, XS, XP and XU.
Modifiers should never be added solely because a claim denied.
The documentation must support their use.
NCCI Edits and AR Follow-Up
Some unpaid claims result from National Correct Coding Initiative edits.
CMS uses NCCI edits to promote correct coding and prevent inappropriate payment when code combinations should not normally be reported together.
Two important concepts include:
Procedure-to-Procedure Edits
PTP edits identify procedure-code combinations that generally should not be separately reported under specified circumstances.
Medically Unlikely Edits
MUEs address the number of units of service that would ordinarily be expected for a procedure.
An AR specialist reviewing a bundling or unit denial should therefore determine whether:
- The coding was incorrect; or
- The services were genuinely separate and the documentation supports an allowable modifier.
CMS emphasizes that modifiers should not be used merely to bypass an NCCI edit. Clinical circumstances and medical-record documentation must support the modifier.
Common AR Denials and How to Work Them
Duplicate Claim — CARC 18
First determine whether the claim truly was submitted previously.
Check:
- Previous claim numbers
- Previous payment
- Corrected claim history
- Resubmission dates
- Voids or replacement claims
Do not repeatedly resubmit claims marked as duplicates.
If the original claim remains unpaid, investigate the original adjudication instead.
Timely Filing — CARC 29
Timely filing denials can quickly become write-offs if not prevented.
Gather:
- Original submission date
- Clearinghouse acceptance report
- Payer acknowledgement
- Claim reference number
- Eligibility information
- Previous payer EOB when COB was involved
Medicare generally uses a 12-month filing period for fee-for-service claims, with limited exceptions.
Commercial insurers and Medicaid programs may use different limits.
Medical Necessity — CARC 50
Medical-necessity denials require more than resubmitting the claim.
Review:
- Clinical documentation
- Diagnosis coding
- CPT/HCPCS coding
- Frequency limits
- Applicable medical policy
- LCD or NCD where relevant
- Prior treatment requirements
- Covered indications
- Requested medical records
If the documentation supports the billed service, an appeal may be appropriate.
If it does not, changing the diagnosis without clinical support is not an acceptable solution.
Bundling — CARC 97
CARC 97 commonly indicates that payment for one service is included in another.
Investigate:
- NCCI PTP edits
- Payer bundling rules
- Procedure relationships
- Same-day services
- Anatomic sites
- Separate encounters
- Applicable modifiers
When supported by documentation, modifiers such as 59, XE, XP, XS, XU or another appropriate modifier may be relevant.
When the services truly are bundled, however, a modifier should not be used merely to force separate payment.
Missing Information — CARC 16
CARC 16 should almost always lead to the associated RARC or payer explanation.
The missing element might be:
- Medical records
- Referral
- Ordering provider
- Modifier
- Procedure code
- Diagnosis
- Units
- Date
- Claim attachment
- Provider identifier
Correct the specific issue rather than blindly resubmitting the claim.
Coordination of Benefits — CARC 22
CARC 22 often means another insurer may be responsible.
Verify:
- Primary versus secondary insurance
- Medicare Secondary Payer information
- Employment coverage
- Workers’ compensation
- Accident information
- Other health insurance
- Patient eligibility
Once COB has been corrected, determine whether the claim should be resubmitted, crossed over, or billed to another payer.
Wrong Payer — CARC 109
A claim routed to the wrong payer or contractor should be corrected quickly.
Verify:
- Member insurance
- Payer ID
- Plan type
- Medicare Advantage versus Original Medicare
- Managed Medicaid versus fee-for-service Medicaid
- Effective dates
Repeatedly submitting the claim to the same incorrect payer only pushes the account further into AR.
Documentation Is Often the Difference Between Payment and Denial
Many AR problems begin well before the claim is submitted.
A physician’s documentation can directly influence whether the coding and medical necessity can be defended.
Depending on the service, the record may need to support:
- Reason for encounter
- History and examination when relevant
- Medical decision-making
- Diagnosis
- Procedure performed
- Anatomic location
- Laterality
- Number of lesions or units
- Drug dose
- Route of administration
- Time requirements
- Treatment plan
- Previous conservative treatment
- Imaging or laboratory findings
- Medical necessity
- Physician order
- Signature and authentication
If the claim is selected for review, payment often depends on whether the documentation supports what was submitted.
CMS contractors may conduct medical reviews and provide denial or non-affirmation reasons when services do not meet applicable Medicare requirements.
Corrected Claim or Appeal: Know the Difference
Not every denial requires an appeal.
Submit a corrected claim when:
The original claim contained a factual billing error that can legitimately be corrected.
Examples include:
- Incorrect modifier
- Typographical error
- Incorrect provider information
- Incorrect units
- Correctable coding error
- Missing claim information
Consider an appeal when:
The claim was submitted correctly but the organization disagrees with the payer’s adjudication.
Examples may include:
- Medical necessity denial despite supporting documentation
- Incorrect bundling determination
- Incorrect coverage interpretation
- Underpayment
- Incorrect contractual adjustment
Follow each payer’s specific corrected-claim and appeal procedures.
Submitting an appeal when the payer requires a corrected claim can delay reimbursement. Submitting a corrected claim when a formal appeal is required can create the same problem.
Underpayments Should Be Part of AR Follow-Up
AR follow-up should not focus only on claims with zero payment.
Underpaid claims can quietly cost a practice substantial revenue.
Compare payer reimbursement with:
- Contracted rates
- Fee schedules
- Allowed amounts
- Expected reimbursement
- DRG/APC methodology where applicable
- Multiple-procedure reductions
- Bilateral rules
- Modifier reductions
- Patient responsibility
- Prior payment history
A claim that was paid is not necessarily a claim that was paid correctly.
Build a Denial Root-Cause Process
Recovering a denial is useful.
Preventing the next 100 similar denials is much more valuable.
For every recurring denial category, identify where the problem originates.
| Denial | Possible Root Cause |
|---|---|
| Eligibility denial | Front-end insurance verification |
| Authorization denial | Prior authorization workflow |
| Invalid diagnosis | Coding or documentation |
| Missing modifier | Coding or charge entry |
| Duplicate claim | Submission process |
| COB denial | Registration/eligibility |
| Medical necessity | Documentation/coding/payer policy |
| Timely filing | Claim submission or AR follow-up |
| Credentialing denial | Enrollment or provider maintenance |
| Bundling denial | Coding/NCCI rules |
Monthly denial reports should show more than denial totals.
Track:
- Denial category
- Payer
- Specialty
- Provider
- CPT/HCPCS code
- Dollar amount
- Root cause
- Recoverability
- Appeal success
- Repeat frequency
This allows physicians and administrators to see whether the organization has an AR problem or an upstream workflow problem.
Often, it is both.
Important AR Metrics for Healthcare Organizations
Days in AR
Measures how quickly receivables are converted into cash.
A rising trend can indicate slower payer processing, growing denials, delayed posting, or ineffective follow-up.
AR Over 90 Days
Shows how much of the receivable balance is becoming aged and harder to collect.
Denial Rate
Measures the proportion of claims or dollars denied.
Track denial rate by reason rather than looking only at a single overall percentage.
First-Pass Resolution Rate
Measures how often claims are successfully processed without needing correction or resubmission.
Clean Claim Rate
Tracks claims submitted without errors that prevent normal adjudication.
Net Collection Rate
Measures how much collectible revenue the organization actually receives after appropriate contractual adjustments.
Appeal Success Rate
Shows whether appeals are being used effectively and whether certain denial categories are worth challenging.
A Practical AR Follow-Up Schedule
Not every payer or claim requires the same follow-up frequency.
A practical approach might look like this:
Early Stage
Confirm acceptance and normal processing.
Avoid calling a payer before its standard processing period has passed unless the claim is unusually large or there is evidence of a problem.
Middle Stage
Investigate unresolved claims.
Check portals, remittances, eligibility, authorization, documentation requests, coding and payer status.
Late Stage
Escalate.
Review filing and appeal deadlines, contact payer escalation channels, submit records, correct claims or appeal where appropriate.
Very Old AR
Determine recoverability.
Prioritize accounts that remain actionable rather than spending excessive resources on balances that have already passed valid recovery options.
AR Follow-Up Example
Consider a clinic that submits an office E/M service and a same-day procedure.
The procedure pays, but the E/M service denies.
The remittance indicates a bundling-related adjustment.
A poor response would be to append modifier 25 automatically and resubmit.
A proper AR review would ask:
- Was a separately identifiable E/M service actually performed?
- Does the physician’s documentation support work beyond the usual pre- and post-procedure service?
- Is modifier 25 appropriate under the payer’s policy?
- Was the claim coded correctly?
- Is an NCCI edit involved?
If the documentation supports the separately identifiable E/M service, correction or appeal may be appropriate.
If the documentation does not support it, the practice should not change the claim merely to obtain separate reimbursement.
That distinction is central to compliant AR management.
Mistakes That Slow Down AR Recovery
Several habits can make accounts receivable worse rather than better.
Rebilling Without Investigating
Repeatedly submitting the same unchanged claim can generate duplicate denials and consume valuable time.
Ignoring Remark Codes
The CARC may provide only part of the explanation. RARCs frequently contain the detail needed to fix the claim.
Adding Modifiers Automatically
Modifiers must be supported by the service and documentation.
Changing Diagnoses for Payment
Diagnosis coding must reflect the patient’s documented condition—not the diagnosis a payer is more likely to approve.
Waiting Until Claims Reach 90 Days
By then, valuable filing or appeal time may already have been lost.
Writing Off Denials Too Quickly
Some denied claims are highly recoverable.
Working Every Claim in the Same Order
AR should be prioritized by age, value, deadlines, denial reason and recoverability.
How Providers Can Improve AR Before the Claim Is Submitted
The strongest AR strategy begins before there is an account receivable.
Physicians, hospitals and clinics can reduce downstream work by improving:
Eligibility verification
Confirm active insurance and benefits before the service.
Prior authorization
Verify authorization requirements and retain reference information.
Provider enrollment
Make sure rendering, ordering, referring and billing providers are appropriately enrolled.
Clinical documentation
Document the service clearly enough to support accurate coding and medical necessity.
Coding accuracy
Use current CPT, HCPCS and ICD-10-CM codes appropriate to the date of service.
Modifier accuracy
Apply modifiers only when the clinical circumstances meet their requirements.
Claim scrubbing
Identify missing or inconsistent information before transmission.
Payer-specific rules
Account for payer differences instead of assuming one billing rule applies everywhere.
Every error prevented before submission is one less claim that needs AR follow-up later.
2026–2027 Coding Considerations for AR Follow-Up
Coding should always be reviewed based on the date of service, not simply the date the AR representative works the account.
As of October 1, 2026, CMS states that the FY 2027 ICD-10-CM files apply to encounters from October 1, 2026 through September 30, 2027.
For older AR claims, the code set that was valid on the original date of service remains important.
This distinction matters when investigating older denials.
A code that is valid today may not have been valid when the original service occurred, and a code that was correct on an older claim may have since been revised or replaced.
Likewise, CMS continues to update CARC and RARC implementation information. A 2026 CMS transmittal specifically addressed updated CARCs, RARCs and Medicare remittance tools.
Organizations managing large AR inventories should therefore maintain access to historical coding and payer-policy information rather than evaluating every old claim using only today’s rules.
A Better Way to Think About Accounts Receivable
AR should not be treated as a department that simply calls insurance companies about old claims.
It is better viewed as a feedback system for the entire revenue cycle.
When AR is analyzed properly, it can reveal:
- Registration failures
- Eligibility problems
- Poor authorization workflows
- Documentation gaps
- Coding inconsistencies
- Modifier errors
- Credentialing problems
- Payer configuration errors
- Contract underpayments
- Claim submission failures
- Slow internal response times
That information should flow back to the people and processes responsible for preventing the problem.
When that happens, AR follow-up changes from reactive collections work into revenue-cycle improvement.
Final Thoughts
Effective AR follow-up in medical billing is not about making repeated payer calls until someone agrees to pay a claim.
It is a structured process of identifying why reimbursement stopped, determining whether the balance is legitimately recoverable, and taking the correct action before the available filing or appeal window closes.
For doctors, physicians, hospitals and clinics, the best AR programs combine claim-status monitoring with accurate coding, strong documentation, payer-policy knowledge, denial analysis, contract review and disciplined follow-up.
CPT, HCPCS, ICD-10-CM codes and modifiers matter because they describe the services being adjudicated. CARCs and RARCs matter because they help explain how the payer processed those services. Neither should be viewed in isolation.
The ultimate goal is not simply to reduce today’s outstanding balance.
It is to create a revenue cycle in which fewer claims become difficult accounts receivable in the first place.
Frequently Asked Questions
What is AR follow-up in medical billing?
AR follow-up is the process of tracking unpaid, underpaid, denied or delayed healthcare claims and taking the necessary steps to obtain the correct reimbursement or financial resolution.
Does AR follow-up have its own CPT or ICD-10 code?
No. AR follow-up does not have a dedicated CPT, HCPCS or ICD-10 code. These codes describe the patient’s healthcare services and diagnoses. AR professionals review them when investigating why the underlying claim did not pay correctly.
What does AR aging mean in medical billing?
AR aging shows how long balances have remained outstanding. Common categories include 0–30, 31–60, 61–90, 91–120 and more than 120 days.
What are CARC and RARC codes?
CARCs explain the general reason a payer adjusted a claim or service. RARCs provide additional information about the adjustment or adjudication. CMS uses these standardized codes on Medicare remittance advice.
What causes most AR problems?
Common causes include eligibility issues, missing authorization, coding errors, incorrect modifiers, medical-necessity denials, bundling, coordination-of-benefits problems, missing documentation, payer processing errors and timely filing issues.
How can healthcare providers reduce AR?
The most effective approach combines accurate patient registration, eligibility verification, authorization, documentation, coding, clean claim submission, payment posting, denial analysis and timely follow-up.