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Common coding problems, from unbundling to undercoding

Medical Economics JournalMedical Economics March 2023
Volume 100
Issue 3

Odds are, you are making these mistakes and missing out on revenue

Q: What are the most common coding mistakes physicians make?

A: As I work with providers across the country, I’ve found many challenges in accurately using current procedural terminology (CPT) and International Classification of Diseases, Tenth Revision (ICD-10) codes. Each time I work with a new office, I find that the same questions and problems are shared by all of us. I’ve broken down some of the challenges that seem to cause sleepless nights.

Not coding to the highest level

For ICD-10 coding, a coder’s job is to code to the highest level of specificity. This means detailing and abstracting the most information out of the medical reports from the provider and taking accurate notes. It also means knowing the medical terminology for both procedures and diagnoses. Check your ICD-10 to ensure that each code assigned has the required number of digits. Not having the right number can lead to a rejected or denied claim.

Not having access to the provider

Ideally, every coder would be in constant contact with the provider they’re coding for. Unfortunately, that’s not always the case. Providers aren’t always available to consult on difficult-to-understand claims, and it might take some time to clarify the coding issues. If you aren’t able to query the provider, less-specific or unspecified codes may need to be billed, which could lead to denials.

Failing to use current
or updated code sets

The organizations that maintain the three principal medical coding code sets — the World Health Organization for ICD-10, the American Medical Association for CPT, and the Centers for Medicare & Medicaid Services for Healthcare Common Procedure Coding System (HCPCS) — update these manuals yearly. Each year, the CPT and HCPCS books are updated January 1 and the ICD book is updated October 1. It’s up to coders to learn any new, revised or deleted codes as they come out and to use them correctly. This is partly why professional organizations such as the AAPC and American Health Information Management Association require members to complete a certain amount of educational credits every two years. Keeping your skills sharp is imperative.

Having bad or missing documentation

Of course, not coding to the highest level isn’t always the coder’s fault. In some cases, the provider hasn’t documented enough specific information for a diagnosis or procedure. Providers may leave important details in their note that are needed to correctly choose a diagnosis, service or procedure. This problem is exacerbated by the next trouble spot on the list.


Unbundling means separately coding procedures that would normally be included in one umbrella code.

This can be due to a misunderstanding or an effort to increase payment. Unbundling is closely related to upcoding, in that it involves false reporting designed to earn the provider a higher payout from a payer. Be sure to check the National Correct Coding Initiative to see if two CPT codes can be billed together and read the description of each CPT code thoroughly to avoid unbundling.

Undercoding and overcoding

Undercoding occurs when codes fail to capture all work performed. This is often due to oversight, but some practices intentionally undercode to avoid an audit. This is not recommended because it results in substantial lost revenue and creates skewed claims data that ultimately lower reimbursement rates.

Overcoding occurs when reporting CPT or HCPCS codes that result in a higher payment than warranted for services provided. Whether intentional or unintentional, overcoding is inappropriate or even fraud, and it can trigger an audit.

Renee Dowling is a compliance auditor at Sansum Clinic, LLC, in Santa Barbara, California.

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