The Most Frequent Coding Errors and How to Avoid Them

Are coding errors silently draining your revenue?
Even the most skilled practices encounter mistakes in documentation, coding, or claim submission. But when errors become patterns, they can quickly snowball into denied claims, compliance risks, and lost revenue. The good news: with the right strategies and checks in place, most errors are preventable.

Let’s take a closer look at the most frequent coding errors and how your organization can safeguard against them.

1. Incorrect Code Selection

Choosing the wrong CPT, HCPCS, or ICD-10 code remains one of the most common mistakes. This often stems from outdated coding references, vague documentation, or confusion between similar codes.

How to avoid it:

• Keep coding resources updated annually.

• Ensure providers supply clear, detailed documentation.

• Encourage coders to verify coding decisions with current payer guidelines.

2. Upcoding and Downcoding

Both unintentional and intentional misrepresentation of services lead to problems. Upcoding inflates reimbursement risk, while downcoding leaves money on the table. Both can trigger audits.

How to avoid it:

• Conduct routine coding audits to catch variances early.

• Train coders and providers on the importance of matching documentation to the level of service.

• Use technology tools, such as encoder software, to flag mismatches.

3. Lack of Medical Necessity

Claims may be coded correctly but still denied if the service isn’t supported by the patient’s diagnosis or clinical documentation. Payers are increasingly scrutinizing “medical necessity.”

How to avoid it:

• Cross-check diagnosis codes with payer-specific coverage policies.

• Train providers to clearly document why the service was performed.

• Use pre-bill edits to catch gaps before claims go out the door.

4. Incomplete or Inaccurate Documentation

If it’s not documented, it didn’t happen. Missing details such as laterality, severity, or encounter type can result in inaccurate coding and claim denials.

How to avoid it:

• Provide physicians with quick-reference documentation checklists.

• Encourage real-time documentation instead of post-visit recall.

• Integrate coding queries to clarify unclear records before submission.

5. Failure to Apply Modifier Rules Correctly

Modifiers are often misunderstood or misapplied, leading to denials for “invalid modifier combinations” or “modifier not allowed.”

How to avoid it:

• Offer focused training on modifier use, especially for high-volume specialties.

• Review payer-specific modifier policies.

• Audit claims with high modifier usage to spot trends.

Why It Matters

Coding errors don’t just slow down reimbursement, they impact your bottom line, compliance posture, and even patient trust. Denials add administrative burden, resubmissions delay revenue, and repeat mistakes can put your organization at risk of audits or penalties. Every coding decision has a direct tie to financial and regulatory health.

How MRS Can Help

At MRS, we partner with healthcare organizations to eliminate costly errors before they affect your revenue cycle. Through:

• Expert coding services backed by certified professionals.

• MRSAuditQ, our proprietary auditing tool, to pinpoint risks.

• Denial management strategies to recover revenue efficiently.

• Training and education to empower your staff with up-to-date knowledge.

Don’t let preventable errors erode your financial health. Contact MRS today to schedule a coding audit or training session and see how we can help keep your organization compliant, accurate, and financially strong.