How payer underpayment happens
Our underpayment recovery services find claims that were paid, but paid less than your contract says, and bring that money back. Insurance underpayment recovery pairs with payer contract review, so you know what each agreement actually promises. Short payments are one of the most overlooked sources of revenue leakage in a practice, and it works alongside our core medical billing services.
A payer underpayment rarely comes from one dramatic error. More often a quiet setup or processing issue repeats across many claims:
- Wrong fee schedule loaded. The payer pays from an outdated or wrong rate table, or a rate increase in your contract was never loaded on the payer side.
- Bundling edits. A service is folded into another code and paid at zero, even when a modifier and the documentation support separate payment.
- Modifier reductions. A modifier triggers a reduced rate when it should not, or the wrong modifier was applied.
- Multiple procedure reductions. Payers commonly reduce payment for additional procedures on the same day. The reduction may be applied to the wrong line or to services the contract excludes.
- Contract terms not applied. Carve-outs, specialty rates, or rates tied to a percentage of a reference fee schedule are not built into the payer's system.
- Provider setup issues. A provider loaded under the wrong specialty, location or group in the payer's system can be paid from the wrong rate table; that is a payer enrollment fix, not an appeal.
How we find underpayments
Knowing how to identify underpayments starts with three numbers on every remittance line, and the difference between them:
| Amount | What it means | Where it comes from |
|---|---|---|
| Billed amount | Your charge for the service | Your practice's fee schedule |
| Allowed amount | The most the payer will pay for the service, including the patient's share | The payer's contracted or out-of-network rate |
| Paid amount | What the payer actually sent | The allowed amount minus deductible, coinsurance and copay |
Allowed amount vs billed amount is not where underpayments show up. The gap between them is normally written off as a contractual adjustment, often reported with CARC 45, which says the charge exceeded the fee schedule or contracted amount. The real test is whether the allowed amount matches the rate your contract sets for that code, modifier and place of service.
- Load the expected rate for each payer and code, then compare it with the allowed amount on every paid line.
- Recalculate the patient share: a correct allowed amount with the wrong deductible or coinsurance still leaves money uncollected.
- Check reductions for multiple procedures, modifiers and bundling against the payer's published policy.
- Watch for rate changes that should have taken effect on a contract anniversary or reference schedule update.
Flags start at posting, where lines that look short are marked instead of adjusted off. Those flags then feed a regular, line-by-line review.
Fee schedule analysis and contract variance analysis
Recovery starts with knowing what you should be paid. Fee schedule analysis means loading the contracted rate for each payer and code, then comparing every paid line against it. Reimbursement validation is that comparison done consistently, line by line, rather than by spot check.
Contract variance analysis, often called payment variance analysis, then sorts the differences:
- Expected. The variance has a valid reason, such as patient cost sharing, an allowed bundling edit or a correct multiple procedure reduction.
- Correctable. The claim itself was wrong, for example a missing modifier or incorrect units, and needs a corrected claim.
- Underpaid. The payer did not pay the contracted rate and the claim should be disputed.
When fee schedules are missing
Many practices never received a complete fee schedule when they signed. Payers often provide rates on request or through their provider portal. Until contracted rates are confirmed, historical allowed amounts for each code can serve as a working baseline.
Contracts tied to the Medicare fee schedule
Many commercial contracts pay a percentage of the Medicare Physician Fee Schedule, so the reference rate has to be current. CMS publishes a Physician Fee Schedule Look-up Tool on cms.gov for a Medicare fee schedule lookup by HCPCS code, year and payment locality. For the Medicare Physician Fee Schedule 2026 rates, the source is the CY 2026 PFS final rule (CMS-1832-F) and the payment files released with it; rates vary by locality and can change with corrections during the year. Because these rates update at least annually, contracts priced from them need to be recalculated each time.
Grouping each payment variance by payer, code and provider shows whether you are looking at one bad claim or a rate problem affecting every visit.
Variance reports
Grouped variance reports turn individual short payments into patterns you can act on. Each report can be cut several ways:
- By payer: shows whether one plan or product line is responsible for most of the variance.
- By code: shows whether a rate for a high-volume service was never loaded or was loaded wrong.
- By provider or location: points to setup problems in the payer's system.
- By month: shows when a problem started, which often lines up with a contract or fee schedule update.
Variance findings appear in your transparent dashboards and monthly performance reporting, and they are reviewed on the monthly call. Custom reports are available on request, for example before a contract renewal.
Our underpayment recovery process
Once a short payment is confirmed, the fix depends on the payer and the cause.
- Reconsideration or reprocessing request. For a clear pricing error, many payers will reprocess a claim through a provider services request or a written reconsideration.
- Formal appeal. When the payer disagrees, the appeal cites the contract section and fee schedule rate, with the remittance showing the amount paid.
- Systemic issues. When the same error hits many claims, we document the pattern so it can be raised with the payer's provider relations contact for a bulk correction.
Appeal deadlines are set by each payer contract and plan, and some are short. Underpayments are worked as soon as they are confirmed, alongside our denial management process.
Payer contract review: what to look for
Our payer contract review reads your agreements for the terms that affect payment, so everyone knows which rates apply. A fee schedule review checks that the rates you received match what the contract describes.
- How rates are set, such as a fixed schedule or a percentage of a reference schedule, and which year's schedule applies.
- Whether the payer can change rates or policies with notice, and how much notice is required.
- Timely filing limits, appeal deadlines and the process for disputing payment.
- Rules on bundling, multiple procedures, modifiers and which payer policies are incorporated.
- How new, changed or unlisted codes will be priced.
- Term length, renewal and termination provisions.
Fastora reviews contracts and fee schedules from a billing and reimbursement perspective. We do not provide legal advice, and contract language should be reviewed with your attorney before you sign or amend an agreement.
Using the data in payer negotiations
Recovery data is useful beyond individual claims. When you approach a payer about rates, facts carry more weight than impressions.
- Your volume by code with that payer, and how its rates compare with your other payers.
- Documented underpayment patterns and how long they took to resolve.
- Denial and administrative burden trends from your monthly reporting.
- What your practice brings to the network, such as specialty services, appointment access or coverage in your area.
Our guide to payer contract negotiation explains how practices prepare for these conversations. Fastora provides the data and billing perspective; payer contract negotiation decisions remain yours.
How it connects to payment posting and AR
Underpayments are easiest to catch when a payment first arrives. During ERA and EOB posting, lines where the allowed amount looks wrong are flagged instead of being adjusted off as contractual.
Flagged claims then stay open in accounts receivable follow-up until they are recovered or confirmed as correct. That keeps the underpaid balance visible in your AR reports instead of hidden in write-offs. To see how this work is scoped and quoted, visit our pricing page.
Contractual underpayment recovery services
As an underpayment recovery company, we find the money payers shorted — not the money they denied. Contractual underpayment recovery services compare every paid claim against your fee schedule and contract terms, line by line, and flag the short pays that add up: wrong fee schedule applied, bundled codes that should have paid separately, units repriced incorrectly. Claim underpayment appeal services then take each underpaid claim back to the payer with the contract language attached — the difference between a phone call that goes nowhere and a documented appeal that gets reprocessed. Most practices discover underpayments are larger than denials once the comparison actually runs. Related: denial management, payer contract negotiation, free medical billing audit.