A practice manager reviewing month-end numbers notices that a common office visit code is paying a few dollars less from one commercial plan than it did last year. Nothing on the remittance looks unusual, and the claims show as paid. Only after pulling the contract does she realize the plan has been paying below the agreed rate for months.

Underpayments rarely announce themselves. Claims post as paid, the balance moves to contractual adjustment or patient responsibility, and the shortfall disappears into normal operations. This article explains how small practices can find underpayments and recover what they are owed.

Why Underpayments Are Easy to Miss

Denials are visible. They generate work queues, reason codes and follow-up tasks. Underpayments are different because the payer does pay, just not the full contracted amount.

Several factors make them hard to spot:

• Automatic posting. Electronic remittances post quickly, and the difference between billed and allowed amounts is often adjusted off without review.

• Small differences per claim. A few dollars per visit does not stand out, but it adds up across hundreds of visits.

• Complex contracts. Many contracts tie rates to a percentage of a fee schedule, and that fee schedule can change each year.

• Limited staff time. Small offices focus on denials and patient balances, leaving paid claims unreviewed.

The result is that many practices never compare what they were paid with what their contracts promise.

Common Causes of Short Payments

Understanding why underpayments happen helps you know where to look.

Fee schedule errors. The payer may load an outdated fee schedule or apply the wrong rate tier to your practice.

Incorrect provider or location setup. If a provider or location is set up incorrectly in the payer's system, claims may be paid at a different rate than the contract specifies.

Multiple procedure reductions applied incorrectly. Payers reduce payment for additional procedures on the same day under multiple procedure rules. Sometimes these reductions are applied to services that should be exempt.

Modifier handling. A modifier that should not reduce payment may trigger a reduced rate, or a modifier may be ignored altogether.

Bundling disagreements. The payer may bundle a service into another procedure where coding rules and documentation support separate payment.

Wrong patient responsibility. The payer may assign too much to the patient, which shows up as a large patient balance rather than a low insurance payment.

How to Compare Payments Against Contracts

Finding underpayments starts with knowing what each payer should pay for your most common services. You do not need to load every code from every contract to make progress.

A practical approach for small practices:

1. Gather your current contracts and fee schedules. Request updated schedules from payers if you do not have them. Many contracts reference a payer's fee schedule or a percentage of Medicare rates for your locality.

2. List your top 20 to 30 procedure codes by volume. These typically represent most of your revenue.

3. Build a simple expected-payment table showing the contracted allowed amount for each code by payer.

4. Pull a sample of recent paid claims and compare the allowed amount on each remittance with your expected amount.

5. Flag any variance above a small threshold for review.

Remittance details help here. The claim adjustment reason codes on an 835 electronic remittance explain why the payer reduced the amount. Contractual adjustments are expected, but unexpected reasons or adjustments larger than usual are worth a closer look.

Underpayment work is one part of managing receivables as a whole. For a broader look at managing receivables, including aging, follow-up and write-off policies, this resource covers the full picture.

Recovering What You Are Owed

Once you have identified underpaid claims, the recovery process is similar to an appeal, though the tone is often more administrative.

Steps that tend to work:

• Group underpayments by cause. If one payer has loaded the wrong fee schedule, address the root cause instead of disputing claims one at a time.

• Contact your provider representative. Share examples, the contract language and the expected rate. Many payers have a process for reprocessing claims once the error is confirmed.

• Submit a formal payment dispute or reconsideration when required. Follow the payer's process and deadlines, which are often in the provider manual.

• Keep records of every contact, reference number and promised correction date.

• Track recovered amounts so you can see the value of the effort.

Many states have prompt payment laws that require insurers to pay clean claims within set timeframes and may apply to underpaid claims as well. If a payer consistently underpays or delays, it may be worth reviewing your state's rules or consulting a healthcare attorney.

Building a Routine Underpayment Review

Underpayment review works best as a regular habit rather than an annual project.

A simple routine for a small practice:

• Monthly: review a sample of paid claims for your top payers and codes

• Quarterly: compare average allowed amounts by payer and code with the previous quarter

• Annually: request updated fee schedules and update your expected-payment table

• At contract renewal: review your history of underpayments as part of negotiations

Some practices fold this work into their regular A/R process. Others assign it to outside help when internal staff do not have the time. Teams that handle underpayment and A/R recovery work can track variances payer by payer and pursue corrections alongside routine follow-up.

Questions to Ask When You Find a Variance

Not every difference between expected and actual payment is an underpayment. Before disputing, it helps to confirm a few points:

• Was the claim billed with the correct codes, units and modifiers?

• Did the payer apply a valid multiple procedure or bundling rule?

• Is the rate in your expected-payment table current for the date of service?

• Was the provider or location listed under the correct contract?

• Did patient cost-sharing account for part of the difference?

Answering these first keeps disputes focused on true underpayments, which improves your credibility with payers and saves staff time. It also often reveals internal billing issues worth fixing, such as modifiers applied inconsistently or outdated codes in templates.

When Patient Balances Hide the Problem

Sometimes an underpayment shows up not as a low insurance payment but as an unusually high patient balance. If a payer applies a deductible or coinsurance incorrectly, the patient receives a larger bill than they should.

Patients who call to question a balance are often pointing to exactly this kind of error. Treat those calls as a signal to check the remittance. Correcting the issue with the payer protects the patient relationship as well as the practice's revenue, and it prevents the frustration of patients paying amounts their plan should have covered.

The Takeaway

A paid claim is not always a correctly paid claim. Practices that know their contract rates, compare them with what payers actually allow, and follow up on variances can recover revenue that would otherwise disappear without notice.

Start small. Build an expected-payment table for your top ten codes and two largest payers, then review one month of claims. The findings will tell you whether a broader review is worth the time.