Surgical coding errors: The cost of incorrect CPT coding

Nov. 1, 2019 / By Karla VonEschen, MS, CPC, CPMA

I find surgical coding to be challenging, but in a good way. I love a good challenge when it’s related to technology, coding or figuring out exactly what procedures a surgeon performed based on documentation. In a way, it’s like putting a puzzle together to make sure you’ve got all the pieces. Surgical coding can be difficult even for the seasoned coder, especially if they have more than one specialty to code. While this is understandable, it’s also the reason why good surgical coders are needed and errors must be kept to a minimum. Coding errors can mean a loss of revenue or potential compliance issues. 

Coding errors for CPT range from not reviewing all the documentation to billing the incorrect number of units. Here are the most common coding errors when it comes to surgical coding:

• Unbundled procedures
• Not coding multiple procedures when appropriate
• Missing charges when multiple procedures are performed
• Coding from the operative note headers rather than reviewing the entire document including procedure details
• Medical necessity not supported
• Incorrect modifier usage
• No documentation of imaging guidance when performed
• Reporting units incorrectly

Incorrect coding can cause a number of issues for a physician from a financial perspective. Let’s consider a simple example:

A physician performed an arthrocentesis on the acromioclavicular joint bilaterally on a 70-year-old female. The coder applied CPT code 20605 (Arthrocentesis, aspiration and/or injection; intermediate joint, bursa or ganglion cyst), but did not read the procedure detail and missed additional information that the procedure was done bilaterally. Therefore, the coder did not append modifier -50 to the surgical code. The insurer processed the claim and paid for unilateral service (100 percent) instead of bilateral service (150 percent).

The Medicare allowed amounts for code 20605: $51.90 (unilateral) and $77.85 (bilateral). The difference between the two reimbursement amounts is $25.95 if a coder does not append the -50 modifier when appropriate. If this procedure is common for a physician and a coder is frequently missing the -50 modifier, the missed reimbursement can add up quickly.

Luckily for coding professionals, there are many resources that can help with appropriately coding surgical services. Some of the most helpful resources include:

• Medicare Administrative Contractor (MAC)
• Medicare Physician Fee Schedule
• NCCI Edits

Of course, don’t forget to always follow guidelines outlined in your CPT code book. 

So, remember that while surgical coding can be a challenge, having the right tools and a detailed approach can make all the difference!

Karla VonEschen is a coding analyst at 3M Health Information Systems.