Article Date: 1/1/2006

billing & coding
Common Coding and Billing Errors
Discovering your mistakes can help you prevent them in the future.

For the past two years, I have overseen the coding and billing procedures of our high-volume student health optometry services at the Ohio State University. Our situation at Ohio State is unique: We are a teaching facility with 40-50 attending doctors, 30 clinic staff and 90-150 rotating student interns providing care at any given time.

I'd like to share our three most common coding and billing errors in hopes of helping you improve your procedures:


By far, our number one coding error has been under-coding. By this, I mean billing a problem-focused evaluation and management (E/M) office visit at a level lower than what the patient history, examination and decision-making support. For example: An established patient presents with a red, irritated right eye after repeatedly sleeping in a soft contact lens not approved for extended wear. A detailed history, expanded problem-focused examination, and mod- erately complex decision-making are appropriately documented in the medical record and support the patient's primary complaint of the red, painful eye. The visit should be coded as an established E/M level three (99213); however, it is billed as a level two (99212). Under-coding by one E/M level will result in a loss of approximately $30 per visit under the medicare fee schedule.

Billable procedures

Our second most common coding and billing error relates to our most common error, but takes under-coding a step further to lack of coding. There are a number of ophthalmic procedures that are billable in addition to the office visit or evaluation and management visit. Corneal topography (92499), gonioscopy (92020), diagnostic imaging (92135), pachymetry (76514), anterior and posterior segment photography (92285 and 92250 respectively) and threshold visual field testing (92083) can be billed separately, and in addition to, the office visit when the procedure is medically necessary.

Through careful record review, we discovered that while we performed and appropriately recorded billable ophthalmic testing many times, we did not complete the process by billing the patient or the patient's medical insurance for the testing. There is also confusion over whether to bill some procedures as bilateral or unilateral. A bilateral procedure is performed on both eyes, but billed once. Threshold visual fields (code 92083) is one example. When you perform a unilateral procedure bilaterally, bill twice with the appropriate –RT and –LT modifiers, or with the -50 modifier. An example of a unilateral procedure code is scanning laser diagnostic imaging, 92135.

Billing office procedures accurately means:

Understand unilateral versus bilateral codes

Document the interpretation and  report

Include accurate modifiers, RT, LT, O.U., -50, -52


Thirdly, in some cases we over-code an examination by billing a level of service such as an E/M level 4, when our medical record documentation supports an E/M level 3. In most of these over-coding situations, we found that the level of service had been performed, but not appropriately documented or in some cases, documented at all. If you take a history or perform testing and don't record it, it is as if you never performed it at all.

Discovering our most common coding and billing errors was the first step to correcting them. Our staff, doctors and interns understand the importance of correct coding as it relates to practice management and the overall value of the services that we provide.


Optometric Management, Issue: January 2006