PHYSICIAN BILLING
AR CALLER INTERVIEW
PREPARATION GUIDE
CMS-1500 • Claim Follow-up • Denial Management • CARC/RARC • Modifiers
Purpose
Use this guide to prepare for an Operations interview for a US Healthcare Physician/Professional Billing Accounts Receivable (AR) Caller role. Learn the workflow and explain examples from your own experience. Do not claim experience you have not performed.
Candidate study material
How to Use This Guide
1. Start with your introduction and the difference between Physician Billing and Hospital Billing.
2. Understand the CMS-1500 claim form and the fields most relevant to AR follow-up.
3. Practise the complete denial workflow: pre-call analysis → payer call → resolution → documentation → follow-up.
4. Revise the common denial scenarios, CARC/RARC concepts, group codes and modifiers.
5. Practise the scenario questions aloud using real examples where possible.
The interviewer's expectation
A strong answer explains what the denial means, what you checked, what you asked the payer, what action you took, and how you documented and followed up. Avoid stopping at “I will call the insurance.”
1. Explain Your Experience Clearly
Prepare a truthful, concise introduction in this order:
Part What to cover
Experience Total US Healthcare/medical billing experience and actual AR Calling experience.
Process Physician/Professional Billing, Hospital Billing, payer types, claim types and clients handled.
Responsibilities Claim status, denial follow-up, eligibility, benefits, appeals, corrected claims, underpayments or other work actually performed.
Denials Name the major denial types you have personally worked.
Performance Daily productivity, quality score, targets and how they were measured.
Systems Payer portals, billing systems, clearinghouse tools and spreadsheets you have used.
Job change Give a professional, factual reason.
Sample introduction framework
“I have [X] years of US Healthcare experience, including [Y] years in [Physician Billing/AR Calling]. My responsibilities include [actual tasks]. I have worked on [actual denials] and use [actual systems/portals] for claim research and payer follow-up. My usual productivity is [true figure] with [true quality metric]. I focus on validating the denial, taking the correct resolution action and documenting the next follow-up.”
2. Physician Billing and CMS-1500 Basics
Topic What you should know
Physician / Professional Billing Billing for services provided by physicians and other eligible professional practitioners.
CMS-1500 Standard paper claim form used for many professional claims; electronic professional claims use the corresponding electronic claim standard.
UB-04 / CMS-1450 Institutional/facility claim form commonly used by hospitals and other facilities.
CPT / HCPCS Codes describing procedures, services, supplies and certain drugs.
ICD-10-CM Diagnosis codes describing the patient's condition.
POS Place of Service: identifies where the service was performed.
NPI National Provider Identifier for providers/entities, as applicable.
EOB / ERA Explanation of Benefits / Electronic Remittance Advice; explains adjudication, payment and adjustments.
CMS-1500: The 33 Main Numbered Items
Know what the fields are used for, especially those connected to the denial you are working. The form has 33 main numbered items, with subfields under several items.
Item Field Purpose
1 Insurance type Identifies the insurance program/type.
1a Insured ID number Member/subscriber identification.
2 Patient name Patient's name.
3 Patient DOB and sex Patient demographics.
4 Insured name Policyholder/subscriber name.
5 Patient address Address and contact details.
6 Patient relationship to insured Self, spouse, child or other.
7 Insured address Policyholder address/contact details.
8 Reserved Reserved for NUCC use.
9 Other insured name Other insurance subscriber, if applicable.
9a Other insured policy/group number Other coverage identifier.
9b Reserved Reserved for NUCC use.
9c Reserved Reserved for NUCC use.
9d Other insurance plan name Other payer/plan details.
10a–10c Related condition Employment, auto accident or other accident indicators.
10d Claim codes Special claim information, when applicable.
11 Insured policy/group/FECA number Primary insurance policy/group identifier.
11a Insured DOB and sex Subscriber demographics.
11b Other claim ID Other claim identifier, when applicable.
11c Insurance plan name Primary plan name.
11d Other health benefit plan? Indicates other insurance coverage.
12 Patient signature Authorization related to release of medical information.
13 Insured signature Authorization related to assignment of benefits.
14 Current illness/injury/pregnancy date Relevant onset/accident date.
15 Other date Additional relevant date.
16 Unable-to-work dates Disability/work absence dates, if applicable.
17 Referring/ordering provider Referring or ordering clinician.
17a Other ID Additional provider identifier, when applicable.
17b NPI Referring/ordering provider NPI.
18 Hospitalization dates Related admission/discharge dates, if applicable.
19 Additional claim information Additional information/qualifiers, as required.
20 Outside lab Outside lab indicator and charges, when applicable.
21 Diagnosis/nature of illness or injury ICD-10-CM diagnosis codes.
22 Resubmission code Claim resubmission/correction information, when applicable.
23 Prior authorization number Authorization/referral number, when applicable.
24 (a–j) Service line DOS, POS, CPT/HCPCS, modifiers, diagnosis pointer, charges, units and rendering provider information.
25 Federal tax ID Provider tax identification number.
26 Patient account number Provider's internal account identifier.
27 Accept assignment? Indicates whether assignment is accepted.
28 Total charge Total billed charges.
29 Amount paid Amount already paid, as applicable.
30 Reserved Reserved for NUCC use.
31 Provider signature Provider certification/signature and date.
32 Service facility location Location where service was provided.
32a Service facility NPI Facility NPI, when applicable.
32b Other ID Additional identifier, when permitted/required.
33 Billing provider information Billing provider name, address and phone.
33a Billing provider NPI Billing provider NPI.
33b Other ID Additional billing provider identifier, when applicable.
Practical field focus
For AR follow-up, pay particular attention to patient/member details (1a–7), other coverage/COB (9–11), dates (14–18), diagnosis (21), resubmission information (22), authorization (23), service-line details including DOS/POS/CPT/modifiers/units (24), patient account number (26), charges/payment (28–29), and rendering/billing/facility details (32–33). Use the current NUCC instructions for exact completion rules.
3. End-to-End AR Claim Workflow
6. Open the account and confirm patient, payer, member ID, claim number and date of service.
7. Review the EOB/ERA and identify the exact denial/adjustment reason, CARC/RARC and group code if present.
8. Check the claim image/data: CPT/HCPCS, ICD-10-CM, modifiers, units, POS, provider NPI, authorization and billed amount.
9. Check eligibility, benefits, network status, coordination of benefits, claim history and previous payment.
10. Review payer rules, timely-filing limit, appeal limit and corrected-claim requirements.
11. Call the payer or use the payer portal. Ask specific questions about the denial and confirm the claim status.
12. Choose the appropriate action: reprocess, corrected claim, appeal, coding/clinical review, eligibility correction, contractual adjustment or escalation.
13. Document payer representative, call/reference number, findings, action taken, turnaround time (TAT), appeal/follow-up deadline and next follow-up date.
14. Track the claim until final resolution and ensure the outcome/payment/adjustment is reflected correctly.
Pre-call checklist
☐ EOB/ERA and denial reason
☐ Claim number and date of service
☐ Patient/member ID and eligibility
☐ CPT/HCPCS, diagnosis, modifiers, units and POS
☐ Authorization/referral
☐ Previous claims and payment history
☐ Payer filing and appeal limits
☐ Supporting records and payer policy
☐ Corrected-claim requirements and next action
4. Denials to Prepare: Definition, Checks and Resolution
Denial Meaning Pre-call checks Resolution / follow-up
Authorization / no authorization on file Payer indicates required authorization is missing, invalid or does not match the service. Check whether authorization was required; validate number, patient, DOS, CPT/HCPCS, units and POS; check portal and records; ask payer whether authorization exists on its side. If valid, request reprocessing. If missing, check whether retro-authorization is permitted and follow the provider's process. If unresolved, evaluate appeal/corrected-claim options. Record reference number and deadlines.
Timely Filing Limit (TFL) Claim was received after the payer's filing deadline, or payer records do not show timely receipt. Compare DOS, submission date, payer received date and payer limit; review clearinghouse acceptance reports, claim acknowledgements and prior payer EOBs. If timely, send proof and request reprocessing or appeal. If late, check exceptions and appeal rights; follow adjustment/escalation policy if no valid remedy.
Inclusive / bundled A service may be considered included in payment for another service. Review CPT combinations, same/different DOS, provider, documentation, prior claim/payment, NCCI edits and modifier support. Request coding review. Correct/rebill or appeal only if documentation and coding rules support separate payment; never add a modifier only to bypass an edit.
Non-covered service Payer indicates the service is excluded or not covered under the plan or policy. Review eligibility, benefits, plan exclusions, DOS, EOB, medical policy and other active coverage; determine whether issue relates to member benefits or provider contract. Follow payer/client rules. Appeal only when coverage or claim processing is incorrect and supported. Do not automatically transfer balance to the patient.
Medical necessity Payer says the service is not supported as medically necessary under its policy. Review diagnosis, CPT/HCPCS, medical records, clinical documentation and applicable payer coverage policy; involve coding/clinical team when required. Submit relevant documentation or appeal if supportable; otherwise follow the appropriate adjustment/escalation process.
Capitation Service may be included in a capitation arrangement rather than separately payable. Check capitation agreement, effective dates, DOS, payer/provider details and service inclusion. If DOS falls within a valid capitation period, follow contract/client process. If not, contact payer and request correction/reprocessing as supported.
Duplicate claim Payer believes the same/similar claim or service was submitted more than once. Compare patient, provider, DOS, CPT, units, claim number, original/corrected indicator and payment history. If truly duplicate, follow adjustment policy. If not, provide claim details and evidence and request reprocessing/appeal as appropriate.
Claim not on file Payer cannot locate the submitted claim. Verify payer ID/address, member ID, claim submission date, clearinghouse status, claim acceptance and claim identifiers. Resubmit only after confirming payer requirements and duplicate risk. If proof shows receipt, ask payer to locate/reprocess and document the reference.
Eligibility / inactive coverage Coverage was inactive or patient could not be matched on DOS. Validate member ID, demographics, effective/termination dates, payer and other coverage. Correct data or identify correct payer; request reprocessing if coverage was active and records support it.
Benefits exhausted / maximum reached Plan benefit limit may have been reached. Check benefit maximum, usage to date, service category and plan period. Confirm correct application of limits; request correction if inaccurate or explain next steps per policy.
Deductible / copay / coinsurance Payer applied member cost-sharing. Review benefit accumulators, EOB/ERA, plan benefits and prior payments. Confirm calculation and group code. Transfer patient responsibility only when permitted and accurate.
Referral / out-of-network Payer indicates referral, network or designated-provider requirements were not met. Check plan type, network status, PCP/referral, authorization, provider participation and DOS. Request correction/reprocessing if payer data is wrong; otherwise follow contract and appeal rules.
Policy terminated Payer indicates coverage ended before DOS. Verify eligibility records, termination date, member details and any replacement coverage. Identify correct payer or correct eligibility information; submit proof/request reprocessing if coverage was active.
Missing documentation / medical records Payer needs supporting information to adjudicate the claim. Identify exact requested records, deadline, submission method and claim reference. Send complete relevant records through approved channel, retain proof of submission and follow up.
Rejection / corrected claim A claim may have failed front-end edits or require correction/resubmission. Identify rejection vs adjudicated denial; review edit message, claim status, original claim number and payer's corrected-claim rules. Correct the specific error and submit using the appropriate original/corrected claim indicator. Avoid creating duplicates.
Appeal A formal request for reconsideration of an adverse determination. Check appeal rights, deadline, address/fax/portal, required form, records, EOB and reason for dispute. Submit a clear appeal with evidence before the deadline; document confirmation and track to decision.
5. EOB, ERA, CARC, RARC and Group Codes
Term Meaning
EOB Explanation of Benefits: payer explanation of how a claim was processed.
ERA Electronic Remittance Advice: electronic remittance details for claim payment and adjustments.
CARC Claim Adjustment Reason Code: explains why a claim or service line was adjusted.
RARC Remittance Advice Remark Code: adds information or clarification about the adjustment.
CO Contractual Obligation group code; commonly provider-side responsibility, subject to contract and rules.
PR Patient Responsibility group code; may represent deductible, copay or coinsurance when correctly applied.
OA Other Adjustment group code.
PI Payer Initiated Reduction group code.
Common CARCs for interview revision
CARC Common interview-level summary
1 Deductible amount
2 Coinsurance amount
3 Copayment amount
4 Procedure code inconsistent with modifier
5 Procedure code inconsistent with place of service
11 Diagnosis inconsistent with procedure
16 Claim lacks information or has a submission/billing error; review accompanying remark
18 Duplicate claim/service
22 Possible other-payer responsibility
23 Impact of prior payer adjudication
26 Expenses incurred before coverage
27 Expenses incurred after coverage ended
29 Filing limit expired
31 Patient cannot be identified as insured
45 Charge exceeds fee schedule/contracted or allowable amount
50 Not medically necessary
96 Non-covered charge(s)
97 Included in payment for another service
109 Claim not covered by this payer; another payer may be responsible
119 Benefit maximum reached for period/occurrence
125 Submission/billing error
150 Documentation does not support level of service billed
167 Diagnosis not covered
170 Service not covered under current benefit plan
197 Authorization/precertification/notification absent
198 Authorization/precertification/notification exceeded
204 Service/equipment/drug not covered under current benefit plan
242 Service not provided by network/primary care provider as required
These are study summaries, not a substitute for the current official code descriptions. Always read the accompanying RARC, payer message and claim context.
Example RARCs to recognize
RARC Study summary
M20 Missing/incomplete/invalid HCPCS code
M51 Missing/incomplete/invalid procedure code
M53 Missing/incomplete/invalid days or units of service
M59 Missing/incomplete/invalid claim information
M62 Missing/incomplete/invalid treatment authorization code
M76 Missing/incomplete/invalid diagnosis or condition code
M77 Missing/incomplete/invalid place of service
M127 Missing patient medical record information
N290 Missing/incomplete/invalid rendering provider primary identifier
N30 Patient ineligible for this service
N519 Invalid combination of HCPCS modifiers
Important
CARC/RARC code sets can be updated and a short description may not explain the full rule. Confirm exact current descriptions in the official code lists and interpret the codes with the group code, payer policy and claim details. Do not assume every denied balance can be billed to the patient.
6. Physician Billing Modifiers
A modifier provides additional information about a procedure/service. Know its meaning, why it is used, when it is appropriate and what documentation supports it. The coding provider/team must determine correct coding; AR should not add unsupported modifiers.
Modifier Common meaning / interview reminder
22 Increased procedural services
24 Unrelated E/M service during postoperative period
25 Significant, separately identifiable E/M service on the same day as a procedure
26 Professional component
50 Bilateral procedure
51 Multiple procedures, when applicable
52 Reduced services
53 Discontinued procedure, under applicable circumstances
54 Surgical care only
55 Postoperative management only
56 Preoperative management only
57 Decision for surgery
58 Staged/related procedure during postoperative period
59 Distinct procedural service, when criteria are met
62 Co-surgeons, when requirements are met
76 Repeat procedure by same physician
77 Repeat procedure by another physician
78 Unplanned related procedure during postoperative period
79 Unrelated procedure during postoperative period
91 Repeat clinical diagnostic laboratory test
93 Synchronous telemedicine, audio-only when applicable
95 Synchronous telemedicine, audio-video when applicable
99 Multiple modifiers
RT / LT Right side / left side
E1 / E2 / E3 / E4 Eyelid location modifiers
GA Waiver of liability statement issued as required by policy
GY Statutorily excluded/non-Medicare benefit, as applicable
GZ Expected denial where required liability waiver was not obtained
JW / JZ Drug amount discarded / no amount discarded, where applicable
KX Applicable medical-policy requirements met
QW CLIA-waived test
XE / XP / XS / XU Separate encounter / separate practitioner / separate structure / unusual non-overlapping service
Modifier 59 and X{escape}-modifiers
Do not use a modifier automatically to overturn an inclusive/bundling denial. Review NCCI edits, documentation, coding guidance and payer rules. Use the most specific valid modifier only when supported.
7. Place of Service (POS)
POS Common description
11 Office
21 Inpatient hospital
22 On-campus outpatient hospital
23 Emergency room – hospital
POS identifies where a professional service was performed. It can affect coverage, reimbursement and claim edits. Confirm the correct POS for the service and payer rules rather than relying on memory alone.
8. Reprocess vs Corrected Claim vs Appeal vs Adjustment
Action When it is used
Reprocess Ask payer to re-adjudicate a claim when it was processed incorrectly or relevant information already on file was not applied.
Corrected claim Resubmit a claim with corrected data following payer instructions and the proper original/corrected claim process.
Appeal Formally challenge a denial when there is a valid basis and supporting evidence.
Adjustment / write-off Post an adjustment only when supported by contract, policy, client process and applicable rules.
Coding / clinical review Route coding or medical-necessity questions to the appropriate qualified team.
Escalation Follow internal escalation paths when payer action is overdue, contradictory or unresolved.
9. Payer Calling: Example Talk Track
Opening: “Hello, I am calling from [provider name] regarding a professional claim. I would like to verify the status and denial details.”
Provide only the payer's required identifiers, such as provider details, member ID, claim number and date of service, after completing authentication.
Investigation: “The claim denied for [reason]. Could you confirm the exact denial rationale and the information currently on file? I have verified [relevant checks].”
Resolution request: “Based on the information confirmed, can this claim be reprocessed? If not, please advise the exact correction/documentation required, submission method and applicable deadline.”
Close: “May I have your name or representative ID, call reference number, expected turnaround time and the next follow-up date?”
Always document
Claim number • DOS • denial reason • payer representative/ID • reference number • payer findings • action taken • TAT • appeal/corrected-claim deadline • next follow-up date.
10. Scenario-Based Practice Questions
Claim denied for no authorization. What will you check before and during the payer call?
Claim denied for timely filing. What proof will you collect and how will you proceed?
Claim denied as inclusive. How will you determine whether the denial is correct?
Claim denied as non-covered. How will you distinguish a plan exclusion from a processing error?
Claim denied for medical necessity. What documents and coding details will you review?
Claim denied under capitation. How will you compare the DOS with the agreement period?
Payer says the claim is a duplicate. How will you check previous submissions and payments?
Payer says claim is not on file. What will you check before resubmitting?
Coverage appears inactive. How will you validate eligibility and identify the correct payer?
How do you identify deductible, copay and coinsurance from an EOB/ERA?
What is the difference between CMS-1500 and UB-04?
What is the difference between CPT/HCPCS and ICD-10-CM?
What is the difference between CARC, RARC and group code?
When might modifier 25, 26, 50, 59, 76 or 77 be relevant?
Explain one real claim you resolved, from pre-call analysis through final outcome.
How do you prioritize aging, high-value, urgent and near-deadline accounts?
What were your actual daily productivity and quality results, and how were they measured?
11. A Strong Structure for Answering Any Denial
15. Define the denial in one sentence.
16. Explain the checks completed before the call.
17. State the exact questions asked of the payer.
18. Explain the evidence and resolution action.
19. Mention documentation, reference number, TAT and next follow-up.
20. Describe the final outcome—or the next step if the claim is still pending.
12. Final Candidate Checklist
☐ Can explain actual experience and daily responsibilities clearly.
☐ Can explain CMS-1500 vs UB-04 and the purpose of key CMS-1500 fields.
☐ Can explain CPT/HCPCS, ICD-10-CM, POS, units, modifiers and NPI.
☐ Can walk through authorization, TFL, inclusive, non-covered, medical necessity, capitation and duplicate denials.
☐ Can explain claim-not-on-file, eligibility, COB, benefits and missing documentation scenarios.
☐ Can distinguish EOB, ERA, CARC, RARC and CO/PR/OA/PI group codes.
☐ Can explain reprocessing vs corrected claim vs appeal vs adjustment.
☐ Can demonstrate a professional payer call and accurate documentation.
☐ Can explain productivity, quality, aging and a genuine claim-resolution example.
☐ Has checked current payer rules and has not memorized code descriptions as universal rules.
Reference Resources
NUCC CMS-1500 claim form and instructions: https://www.nucc.org/index.php/1500-claim-form-mainmenu-35/1500-instructions-mainmenu-42
CMS remittance advice guidance (CARC/RARC context): https://www.cms.gov/medicare/coding-billing/electronic-billing/health-care-payment-remittance-advice
CMS National Correct Coding Initiative (NCCI): https://www.cms.gov/medicare/coding-billing/national-correct-coding-initiative-ncci-edits/medicare-ncci-policy-manual
Final advice: Understand the process; do not just memorize answers.⚠️Content was pasted as plain text and auto-formatted as a code block. Use the Code Block button in the editor for proper formatting.