5 Medical Billing Mistakes That Are Costing Your Practice Money

Most practices don't realize how much revenue they're leaving on the table. From upcoding errors to missing modifiers, these five billing mistakes are the most common — and the most costly.

For most medical practices, billing is an afterthought — something that happens in the background while the real work of patient care takes center stage. But billing errors are one of the most consistent sources of revenue loss in healthcare, and the mistakes are often preventable.

Here are the five most common medical billing mistakes we see — and what to do about them.

1. Upcoding or Downcoding Evaluation & Management (E/M) Visits

Selecting the wrong E/M level is one of the most frequent and costly coding errors. Upcoding — billing for a higher level of service than documented — creates compliance risk and potential repayment liability. Downcoding — billing below what the documentation supports — leaves legitimate revenue uncollected. Both stem from the same root cause: inadequate documentation or insufficient coder training on E/M guidelines.

2. Missing or Incorrect Modifiers

Modifiers communicate critical context to payers — whether a procedure was bilateral, performed by multiple providers, or done during a global period. Missing a modifier like -25 on a same-day E/M and procedure visit, or incorrectly applying -59 to unbundle services, leads to automatic denials that require rework and delay payment.

3. Failing to Verify Eligibility Before the Visit

Submitting a claim for a patient whose coverage lapsed — or who is enrolled in a plan your practice doesn't accept — results in an immediate denial with no path to recovery. Real-time eligibility verification before every visit eliminates this category of denial entirely.

4. Ignoring Denied Claims

Industry data suggests that up to 50% of denied claims are never resubmitted. Practices accept the denial, write off the balance, and move on. This is one of the most significant sources of preventable revenue loss. Every denial deserves a response — whether that's a corrected resubmission or a formal appeal with supporting documentation.

5. Letting Accounts Receivable Age Past 90 Days

Once a claim crosses the 90-day mark without resolution, the probability of collection drops sharply. Most payers have timely filing limits that can permanently close the door on reimbursement. Active AR management — working aging buckets weekly and escalating stalled claims before deadlines — is the difference between recovering revenue and writing it off.

The Bottom Line

Each of these mistakes is fixable. The practices that recover the most revenue aren't necessarily the ones with the most patients — they're the ones with the most disciplined billing processes. If any of these issues sound familiar, HEMBILLING's certified team can help identify where revenue is leaking and close those gaps.