When to use this playbook
You need more than a suspicion that reimbursement looks low. Your goal is to prove, claim by claim, whether the payer used the wrong contracted rate and to separate recoverable pricing errors from coding, eligibility, and patient-responsibility issues.
- A payer’s allowed amounts changed without a clear contract amendment.
- The same CPT or HCPCS code is paid at inconsistent rates across otherwise comparable claims.
- A new agreement or rate increase was signed, but claims still appear to use the prior fee schedule.
- A remit includes an unexplained PPO or network discount.
- You suspect underpayment extends across months or years and need a defensible recovery package.
What success looks like
A successful audit identifies the affected payer, product, network, entity, date range, and claim lines; calculates the expected and actual allowed amounts; assigns a root cause; preserves every applicable deadline; and produces a documented request for correction and bulk reprocessing.
| Element | What you need | What it proves |
|---|---|---|
| Governing rate | Contract, rate exhibit, amendment, code-specific confirmation, or matched in-network rate data | What the claim should have allowed on its date of service |
| Submitted claim | CPT or HCPCS code, modifiers, units, place of service, NPI, TIN, and billed charge | What the practice actually asked the payer to adjudicate |
| Adjudication record | 835 ERA or EOB showing allowed amount, payer payment, patient responsibility, adjustments, CARCs, and RARCs | How the payer priced or edited the line |
| Deadline record | Corrected-claim, reconsideration, appeal, contract-dispute, recoupment, and offset-challenge windows | Which submission path remains available and when action is due |
Step 1: Freeze the deadlines before analyzing the full history
Action: Build a deadline register for the payer before investigating every suspected claim. Record the original filing limit, corrected-claim limit, first-level appeal or reconsideration window, contract-dispute process, recoupment or offset challenge window, submission address or portal, and the event that starts each clock.
As of October 9, 2026, Original Medicare claims generally must be filed within one calendar year of the date of service, while a Medicare fee-for-service redetermination generally must be requested within 120 days after receipt of the initial determination. Medicare reopening rules are separate: a determination can be reopened within one year for any reason and within four years when good cause exists. Commercial payer deadlines differ, so use the executed contract, current provider manual, remittance notice, and recoupment notice rather than applying Medicare’s rules to commercial claims. CMS Medicare timely-filing guidance, CMS Medicare redetermination guidance, and CMS reopening manual.
Expected outcome: You know which claims need immediate action and can protect recent recovery rights while the broader audit continues.
Gotchas: Timely filing, appeal filing, contract disputes, and recoupment challenges can run on different clocks. Do not assume that a claim submitted on time can still be appealed indefinitely, or that a two-year suspected pattern means every claim remains eligible for the same recovery route.
Time estimate: 60 to 90 minutes when the contract and provider manual are organized; longer when terms are distributed across amendments and portal notices.
Step 2: Establish the rate that governed each date of service
Action: Collect the executed participation agreement, fee-schedule exhibits, amendments, effective-date notices, product attachments, network-access provisions, and the provider manual version applicable to the audit period. Request both current and historical schedules when rates changed during the period.
If the payer will not release a complete fee schedule, use the strongest available option for the codes that carry your revenue. Keep proof of the request and distinguish contractual evidence from market benchmarking.
| Option | What to request or collect | How to use it |
|---|---|---|
| Targeted code request | Written rates for selected CPT or HCPCS codes, including modifiers, units, place-of-service rules, effective dates, and product or network | Use this first for the highest-dollar and highest-volume codes rather than waiting for the entire schedule. |
| Reimbursement methodology | Confirmation that payment uses a fixed amount, percentage of Medicare, discount from charges, internally defined maximum allowable, or another formula | Recreate the expected amount only after identifying every input required by the formula. |
| Provider portal estimate | Code-specific estimates, rate lookups, or claim-pricing results with dated screenshots or exports | Use as payer-generated corroboration and retain the date, product, provider, and place-of-service inputs. |
| Prior correctly priced claims | Earlier remittances for the same code and matching product, network, entity, modifiers, units, and place of service | Use to identify a change or configuration inconsistency, not as a substitute for the governing contract. |
| Transparency in Coverage data | Matched in-network rate data for the correct billing code, plan, NPI, TIN, place of service, and effective period | Use as a fallback or benchmarking reference when direct contract records remain incomplete. |
Most group health plans and issuers must publish machine-readable in-network rate files, but these files can be extremely large and require technical processing. The federal specifications associate rates with identifiers including NPI, TIN, and place of service, so a rate found under the wrong entity or location is not adequate proof of your contract. The files are also updated monthly without a federal requirement to retain every prior monthly version, which makes dated exports important for a historical audit. CMS Transparency in Coverage guidance and CMS technical clarification.
Expected outcome: Every audited claim line has a documented rate source, reimbursement formula, and effective date rather than an assumed benchmark.
Gotchas: Check for “lesser of billed charges or contracted rate” language. A claim billed below the fee schedule may be correctly allowed at the lower charge. Also confirm that the schedule applies to the exact payer product, network, TIN, location, provider type, and date of service.
Time estimate: Two to four hours to assemble internal documents; payer retrieval may take substantially longer.
Step 3: Build and read the claim-line 835 audit file
Action: Download the raw 835 files or a line-level ERA export from the clearinghouse, payer portal, or practice-management system. Do not use the EFT deposit, a claim-level summary, or a PDF remit as the primary reconciliation file when structured 835 data is available. One row should represent one adjudicated service line, not one patient, encounter, claim, or deposit.
| Category | Fields to capture |
|---|---|
| Contract identity | Payer, product, network, TIN, billing NPI, rendering NPI, location |
| Claim identity | Claim number, payer claim-control number, line number, patient control number, date of service, 835 trace number |
| Service details | CPT or HCPCS code, modifiers, units, place of service, billed charge |
| Expected result | Rate source, expected allowed amount, applicable adjustment methodology |
| Actual result | Payer-reported or reconstructed allowed amount, line payment, patient responsibility, adjustment group, CARC, RARC, and any provider-level adjustment |
| Recovery status | Variance, root cause, filing deadline, dispute number, submission date, recovered amount |
Read each service line in this order:
- Identify the submitted charge, code, modifiers, units, and date of service.
- Capture the payer-reported allowed amount when the 835 parser or ERA report exposes it.
- Separate CO adjustments, which assign an amount to the provider as a contractual obligation, from PR adjustments, which assign patient responsibility.
- Record every CARC and RARC so pricing reductions are not confused with bundling, unit, eligibility, medical-policy, or coding edits.
- Keep Provider-Level Balance adjustments separate because a PLB can change the EFT without changing the allowed amount of any individual claim line.
On a simple line containing only a contractual discount and patient responsibility, the allowed amount should reconcile in two directions: billed charge minus the contractual reduction, and payer payment plus patient responsibility. If those calculations do not balance, review the remaining line-level and claim-level adjustments rather than forcing the difference into an underpayment category. CMS explains that 835 adjustments can occur at the service-line, claim, or provider level, with CO and PR group codes assigning different financial responsibility. CMS payment and remittance guidance.
Expected outcome: You can calculate and filter variances without confusing claim pricing, patient responsibility, and unrelated payment offsets.
Gotchas: Do not compare the contracted rate directly with the EFT deposit or payer-paid amount. Compare it with the adjudicated allowed amount; deductibles, coinsurance, secondary-payer coordination, and provider-level adjustments affect cash without necessarily changing the contracted allowance.
Time estimate: Half a day when clean claim and ERA exports are available; several days when staff must transcribe PDF remits.
Step 4: Audit the CPT codes where errors will matter first
Action: Rank codes separately by total allowed dollars and paid-line volume. Begin with the codes near the top of both lists, then add codes exposed to modifier, unit, place-of-service, or recent contract-amendment errors.
| Priority | Code group | Why it comes first |
|---|---|---|
| 1 | Codes producing the most total allowed dollars | A percentage or fixed-dollar error creates the largest financial exposure here. |
| 2 | Highest-frequency codes | A small recurring variance can become material when repeated across hundreds of lines. |
| 3 | Codes already showing inconsistent allowables | Different payments for matching claim attributes often reveal product, schedule, or configuration differences. |
| 4 | Modifier-, unit-, or place-of-service-sensitive services | Professional and technical components, bilateral services, timed therapy, multiple procedures, and telehealth can be priced differently. |
| 5 | Recently amended rates and negotiated carve-outs | These expose stale fee-schedule loads and incorrect effective dates quickly. |
For primary care, the first group often includes office and outpatient evaluation-and-management families. Behavioral health groups commonly start with diagnostic and recurring psychotherapy services; therapy practices start with high-volume timed treatment codes; procedure-heavy groups prioritize professional, technical, bilateral, and multiple-procedure combinations.
Expected outcome: A focused sample reveals whether the problem is isolated, code-specific, or systematic before the team audits every line.
Gotchas: Do not review only denied claims. A payer can pay every claim while consistently applying an outdated or unauthorized rate.
Time estimate: Two to four hours to rank codes and select a defensible initial sample.
Step 5: Reconcile each line and rule out valid reductions
Action: Recalculate the expected allowed amount using the rate and methodology in effect on the date of service. Then subtract the actual allowed amount:
Potential underpayment = expected allowed amount - actual allowed amount
Worked reconciliation: testing one remittance line
This illustrative line contains a billed charge of $150 and a fixed contracted allowance of $120. The 835 reports a $30 CO-45 contractual adjustment, $20 of patient responsibility, and a $100 payer payment.
| Component | Amount | Reconciliation test |
|---|---|---|
| Submitted charge | $150 | Starting amount on the claim line |
| CO-45 contractual reduction | $30 | $150 minus $30 produces a $120 allowed amount |
| Patient responsibility | $20 | This changes who pays the allowance, not the allowance itself |
| Payer payment | $100 | $100 plus $20 patient responsibility equals the $120 allowance |
| Expected contracted allowance | $120 | The line matches the contract, so the variance is $0 |
If the governing rate exhibit instead set the allowance at $135, the expected contractual reduction would be $15. With $20 still assigned to the patient, the payer payment would ordinarily need to total $115 when no other adjustment applies. The actual $100 payment would then reflect a $15 allowed-amount variance. CARC 45 identifies a reduction from the submitted charge to a fee schedule, maximum allowable, or contracted amount, but it does not prove that the payer selected the correct contract or rate. X12 Claim Adjustment Reason Codes.
Contract terms that can make a low payment correct
| Clause or payment rule | Potentially correct calculation | How to distinguish it from an error |
|---|---|---|
| Lesser of billed charges or fee schedule | The expected allowance is the lower of the submitted charge and the contracted rate. | Compare the billed charge with the fee-schedule amount. If a $120 contracted service was billed at $100, a $100 allowance can be correct. Billing below the schedule can permanently cap revenue for that claim. |
| Percentage of Medicare | The expected allowance is the contract percentage multiplied by the specified Medicare base. | Confirm the Medicare year, locality, facility or nonfacility amount, modifier treatment, and update rule. A payer can produce the wrong amount by using the wrong year or locality even when it applies the stated percentage correctly. |
| Bundling or payment-policy edit | One service is included in another service under the payment policy governing the contract. | Identify the exact policy, CARC, RARC, code pair, and modifier treatment. Treat the issue as an adjudication dispute rather than a fee-schedule error when the rate itself was not the cause. |
| Multiple-procedure reduction | The primary procedure is paid at its applicable rate and one or more additional procedures receive a defined reduction. | Confirm that the code, sequence, provider, patient, and date of service meet the applicable policy. Check whether the payer reduced the correct component and recognized any valid modifier. |
| Rental or leased-network rate | A downstream payer applies a rate it can access through an authorized network agreement. | Require the payer or administrator to identify the network, contracting entity, applicable clause, fee schedule, TIN, product, and effective date. An unfamiliar payer name alone does not establish an unauthorized discount. |
For a percentage-of-Medicare contract, select the exact fee-schedule year and locality specified in the agreement before applying the percentage. The CMS Physician Fee Schedule tool supports searches by year, code, locality, and payment-policy indicator, including indicators relevant to multiple-procedure adjustments. CMS Physician Fee Schedule Look-Up Tool.
| What the claim shows | Likely classification | Next move |
|---|---|---|
| Same code, units, modifiers, place of service, and eligibility, but actual allowed is below the governing rate | Contract-pricing or fee-schedule loading error | Submit a rate dispute and request corrected pricing. |
| Allowed amount is correct, but payer payment is lower because of deductible or coinsurance | Patient responsibility, not payer underpayment | Follow the patient-balance and secondary-payer workflow. |
| The payer reduced units, changed the code, bundled services, or ignored a modifier | Coding or adjudication dispute | Validate the claim and documentation against the applicable edit or payment policy. |
| The remit cites provider eligibility, enrollment, location, or effective-date problems | Credentialing or enrollment issue | Prove the correct effective status and pursue claim reprocessing. |
| The claim line is correct, but the EFT is lower because of a provider-level deduction | Payment reconciliation issue | Reconcile the PLB separately from the claim. |
CARCs and RARCs identify the payer’s stated adjustment reason, but a contractual-obligation adjustment does not prove that the correct contract or schedule was loaded. Coding edits also require separate validation: CMS’s NCCI framework distinguishes procedure-to-procedure edits, medically unlikely units, and modifier-sensitive situations, while commercial payers can implement their own payment policies. CMS ERA standards and CMS NCCI guidance.
Expected outcome: Each variance is assigned to the correct operational owner: contracting, billing, coding, credentialing, eligibility, or payment posting.
Gotchas: Do not label a downcoded, bundled, noncovered, or ineligible service as a fee-schedule underpayment. Conversely, do not accept a contractual adjustment merely because the remit assigned it to the provider.
Time estimate: Half a day for a focused sample, assuming the historical rates and claim attributes are available.
Step 6: Test unexplained discounts for a silent PPO or leased-network issue
Action: Compare four entities for each suspect claim: the insurer on the member card, the claims administrator, the organization that priced the claim, and the network whose discount was applied. Search the remit for network identifiers, repricer names, healthcare-policy references, or wording such as “PPO discount.”
Ask the payer or administrator to provide, in writing:
- The contract and network used to price the claim.
- The contracting entity that authorized access to the discount.
- The product and effective date to which that access applies.
- The contract clause permitting affiliate, third-party, or rental-network access.
- The fee-schedule version and rate applied to the disputed line.
Rental networks can legitimately lease contracted discounts when the agreement authorizes access. The problem is an unexplained or unauthorized discount. The American Medical Association recommends checking whether a valid PPO contract applies when a remit uses “PPO Discount” to justify reduced payment. Arctic Health’s contract-audit method starts with both sides of the relationship: executed agreements and paid claims, then maps each payer or administrator back to the network and TIN that supplied the rate. AMA fair-contracting guidance and Arctic Health rental and leased-network guide.
Expected outcome: You can trace the discount to an authorized contract path or document that the payer has not established which agreement supplied the rate.
Gotchas: A different administrator or payer name is not automatically evidence of a silent PPO. Self-funded plans, third-party administrators, and authorized leased networks can produce legitimate differences between the card, remit, and contract names.
Time estimate: One to two hours per suspect network once the contract, remit, and payer contacts are available.
Step 7: Submit the right recovery package through the right channel
Action: Match the submission route to the root cause. Use a corrected claim only when the submitted claim data was wrong. Use a reconsideration, appeal, or contract-rate dispute when the original claim was correct but the payer priced or edited it incorrectly.
| Problem | Submission route | Requested remedy |
|---|---|---|
| Incorrect code, modifier, units, NPI, or other submitted data | Corrected claim | Readjudication using corrected claim information |
| Correct claim priced under the wrong fee schedule | Contractual rate dispute or claim appeal | Corrected allowance and payment |
| Identical claims continue to use an old rate after an amendment’s effective date | Provider relations or contracting escalation with a configuration-error claim schedule | Retroactive fee-schedule correction and bulk reprocessing |
| Unauthorized network discount | Contract dispute and network-access escalation | Removal of the discount and repricing under the governing arrangement |
| Provider incorrectly marked ineligible | Enrollment escalation followed by reprocessing request | Correction of payer records and readjudication of affected claims |
A repeatable wrong rate across matching claims is usually more useful evidence of a payer configuration problem than one isolated variance. The pattern becomes especially strong when every affected line shares the same payer, product, network, TIN, code, and date range, or when claims continue to use the prior schedule after a documented amendment. Ask the payer to open a fee-schedule configuration ticket and identify the complete claim population for bulk reprocessing rather than closing the matter after correcting the sample claims.
Attach the executed contract or applicable excerpt, rate exhibit, amendments, sample claims, original claim data, ERAs, expected-rate calculations, eligibility evidence when relevant, prior correctly priced examples, prior correspondence, and proof of timely submission. Include a spreadsheet listing every known affected claim and identify the fields the payer can use to reproduce the pattern.
A strong cover letter states the payer, product, network, TIN, NPI, date range, rate source, observed error, total known variance, earliest deadline, and requested remedy. The AMA’s claim-payment guidance recommends supporting an appeal with contractual information, coding or CMS guidance, prior correct adjudications, and transmission evidence when filing time is disputed. AMA claim-payment appeal guidance.
Expected outcome: The payer receives a reproducible calculation and a specific correction request that can be routed to claims configuration, contracting, enrollment, or provider relations.
Gotchas: A generic “please reconsider” appeal is easy to close without addressing the rate error. Do not submit a corrected claim when no claim field changed, and retain portal confirmations, reference numbers, delivery receipts, and copies of every attachment.
Time estimate: Half a day to create the first complete recovery package; later claims should follow the same evidence template.
Step 8: Size the full variance and verify recovery
Action: Once a sample confirms an error, query the full claims history using the characteristics that define the pattern: payer, product, network, TIN, NPI, location, CPT or HCPCS code, modifier, units, place of service, date range, and actual allowed amount. Do not extrapolate one claim across two years when the full line-level population can be tested.
| Measure | Calculation | Why it matters |
|---|---|---|
| Affected lines | Count of matching claim lines after exclusions | Shows whether the issue is isolated or systematic. |
| Expected allowed amount | Sum of the governing allowance for every affected line | Establishes what the payer should have allowed under the tested methodology. |
| Actual allowed amount | Sum of the payer-adjudicated allowance for the same lines | Measures the adjudicated value without mixing in patient responsibility or PLBs. |
| Gross identified variance | Sum of positive line-level differences between expected and actual allowance | Sizes the suspected underpayment before deadline and dispute-route review. |
| Variance rate | Gross identified variance divided by expected allowed amount | Allows comparison across codes, products, locations, and months. |
| Amount within the stated dispute window | Variance on claims that meet the applicable payer or contract deadline | Separates current submissions from older claims requiring a different escalation path. |
Separate claims into three queues:
- Claims approaching a filing or appeal deadline.
- Claims safely within the standard dispute window.
- Older claims requiring contract-level escalation, a reopening request, or other specialized review.
Track the amount identified, submitted, acknowledged, adjusted, paid, denied, and still unresolved. Reconcile each recovery against the replacement remit and actual deposit; a payer response promising adjustment is not completed recovery.
Expected outcome: A single confirmed pricing error becomes a controlled recovery project with a measurable outstanding balance and accountable follow-up.
Gotchas: Payers sometimes correct only the sample claims. Keep the dispute open until the fee-schedule configuration is fixed, the full affected population is addressed, and future claims begin pricing correctly.
Time estimate: Several hours to expand a clean, well-defined pattern; ongoing review should be scheduled weekly until payment and configuration are reconciled.
When a claim audit becomes a payer-operations problem
A small number of isolated claim errors can usually stay with billing staff. Outside payer-operations support becomes more useful when the evidence spans multiple contracts, networks, TINs, locations, enrollment records, or fee-schedule versions.
Arctic Health is the best fit when…
- The suspected underpayment overlaps with contract loading, network access, provider enrollment, effective dates, or roster accuracy.
- Your organization needs fee-schedule review, CPT-level rate benchmarking, remittance reconciliation, and payer follow-up in one workflow.
- A practice acquisition, ownership change, new TIN, or multi-state structure makes it unclear which agreement should govern each claim.
- Your internal team can identify suspicious payments but lacks the capacity to trace the payer relationship and pursue bulk recovery.
Arctic Health connects payer contract and fee-schedule review with rate benchmarking, remittance reconciliation, network-access audits, appeals, and payer follow-up. That connected model is most valuable when an apparent payment variance could have originated in the contract, a leased network, fee-schedule configuration, or the operational payer setup. Arctic Health payer contracting and rate negotiation.
Arctic Health is not a fit when…
- You have one straightforward claim with an obvious data-entry error that only requires a corrected claim.
- The sole issue is whether clinical documentation supports the billed code and you need a specialized coding or clinical documentation audit.
- Your experienced payer-contracting and RCM teams already have the governing schedules, automated contract-versus-remit reconciliation, and established payer escalation paths.
Arctic Health provides managed payer operations for organizations that need execution as well as workflow visibility; it does not guarantee a particular reimbursement or recovery outcome. Arctic Health services.
Frequently asked questions
We think one payer has underpaid us for two years. How do we prove it and recover it?
Start with the newest claims, preserve every approaching deadline, and then test the full two-year population at the service-line level. Establish the historical rate or formula for each date of service, reconcile the 835 allowed amount against that rate, rule out legitimate contract reductions, and group identical variances by payer, product, network, TIN, code, and effective period. Submit representative claims with the full affected schedule and request both a configuration correction and bulk reprocessing. Older claims can have different submission options, so keep the identified two-year variance separate from the amount that falls within the payer’s stated dispute window. AMA payment-dispute guidance.
How do I compare what I was paid against my contracted fee schedule?
Compare the expected contracted allowance with the actual allowed amount for each service line, not with the EFT or payer payment alone. Match the CPT or HCPCS code, modifiers, units, place of service, date of service, product, network, TIN, and NPI. On a simple claim, the allowed amount equals the payer payment plus patient responsibility, and it also equals the billed charge minus the contractual reduction. Deductibles and coinsurance divide the allowance between payer and patient; they do not by themselves prove underpayment. CMS remittance guidance.
What can I do if the payer will not provide a complete fee schedule?
Request written rates for the CPT and HCPCS codes that produce the most revenue, along with effective dates, product, network, modifier, unit, and place-of-service rules. Also request the reimbursement formula, use dated portal estimates, retain prior correctly priced claims, and extract matched Transparency in Coverage rates when direct records remain incomplete. Treat public market rates and unmatched payer data as benchmarking evidence rather than automatic proof of your contractual entitlement. CMS in-network rate-file guidance.
How do I benchmark reimbursement rates against other practices in my market?
Benchmark the CPT codes that drive your revenue against three references: your other commercial contracts, the applicable Medicare locality and fee-schedule year, and matched Transparency in Coverage rates for comparable providers and settings. Compare code-level allowables rather than a single headline percentage because weak pricing can be concentrated in a small number of high-volume services. Benchmarking can show that a contract is economically weak, but only the governing contract and remittance reconciliation can prove that a payer underpaid a claim. Arctic Health provides rate benchmarking and fee-schedule review for small and mid-sized groups. Arctic Health commercial rate-negotiation playbook.
What does “the lesser of billed charges or the fee schedule” mean for revenue?
The clause means your submitted charge can cap the allowed amount even when the contracted fee schedule is higher. If the fee schedule allows $120 but the practice bills $100, the expected allowance is generally $100 under that formula, not $120. A practice that routinely bills below contracted rates can therefore lose revenue without the payer making a pricing error. Test billed charges against every material fee schedule before concluding that low allowed amounts are underpayments. Arctic Health payer contract clause guide.
How do I tell whether a low payment includes a silent PPO discount?
Trace the discount to the contract that supposedly authorized it. Compare the insurer, administrator, repricer, and network named across the card, claim, remit, and contract, then request the clause granting that entity access to your negotiated rate. Wording such as “PPO Discount” or an unfamiliar network name is a reason to investigate, not final proof. Authorized rental-network access can be legitimate; an unexplained discount without an identified contract path is the actual issue to escalate. Arctic Health rental and leased-network guide.
References
- Arctic Health payer contracting and rate negotiation services
- Arctic Health payer contract clause guide
- Arctic Health rental and leased-network guide
- CMS health care payment and remittance advice
- X12 Claim Adjustment Reason Codes
- CMS Transparency in Coverage pricing information
- CMS in-network rate-file technical clarification
- CMS Physician Fee Schedule Look-Up Tool
- CMS National Correct Coding Initiative
- CMS Medicare redetermination process
- AMA guide to identifying and appealing claim-payment issues