One of most recognizable American icons, the diner is a place that symbolizes a strong, inherent sense of community. And just about anyone who has frequented a diner likely has experienced the quintessential diner staple: the toasted corn muffin, typically served cut in half, separating the muffin top from the bottom, and toasted golden brown on a griddle.

Did you ever wonder why these muffins are never cut into identical halves, each containing a portion of muffin top and bottom? It’s not that the bottom portion is no good; however, the muffin top typically is the coveted portion, so sharing a toasted corn muffin sometimes can be problematic. Is there some American or International Culinary Center standard for muffin-cutting that results in the separation of the top from the bottom? Ask any diner cook why the muffin is cut in this manner, and regardless of their formal or informal culinary training, they likely will provide a very simple answer: that is the way it is done.

Quiet the Inner Voice

So what do toasted corn muffins have to do with ICD-10 coding? When I attended the American Health Information Management Association (AHIMA) Academy to become an AHIMA ICD-10-approved trainer, many parallels between ICD-9 and ICD-10 were presented in the curriculum. The in-person workshop education sessions I attended included approximately 60 experienced ICD-9 coding experts with numerous years of experience. These accomplished coding professionals included consultants, coding managers, supervisors, DRG quality coordinators, educators, etc. The goal for the development of the AHIMA Academy was for participants to become proficient in the ICD-10-CM and/or ICD-10-CM/PCS coding systems while preparing to train others. Therefore, participants are required to meet several specific standards and rigorous prerequisites for taking part in this advanced learning program. There are numerous, significant differences between ICD-9-CM and ICD-10-CM/PCS coding guidelines and conventions. Many participants, myself included, hoped to come to understand the reasoning behind certain ICD-10 guidelines and/or conventions, as they were significantly different and sometimes contradictory to those of ICD-9. The justification behind some of these ICD-10 guidelines and conventions was very simple; that is the way it is done. 

As the group advanced through the curriculum with the instructors, many coding vignettes were presented to participants for discussion and comprehension. As the two-day workshop continued, and more examples of the differences between ICD-9 and ICD-10 were presented, some very lively discussions occurred. While the first reaction to some of these differences was to question whether these guidelines and conventions were appropriate, when learning ICD-10-CM/PCS coding, one must quiet his or her inner voice and recognize that things are going to be very different.

For example, consider a case in which a right mastectomy with a free TRAM flap reconstruction is assigned one procedure code for the free TRAM flap procedure. No code is assigned for the mastectomy, as this was not the intent of the procedure. The ICD-10 index reference for reconstruction lists three choices for the root operation for this procedure, including repair, replacement and supplement. Since the root operation was to replace the body part of the right breast, only one procedure code is assigned for a mastectomy with a free TRAM flap. The ICD-10 guideline for replacement includes taking out the body part; therefore, the mastectomy is not coded separately. From a statistical and data capture perspective, one can present a logical argument that this coding guideline will result in the underreporting of procedures and resources consumed for replacement procedures such as the one outlined above. Resulting may be difficulties in identifying patient populations that have undergone a mastectomy with free TRAM flap reconstruction.


Understanding the intent of the procedure and applying the correct ICD-10 root operation definition will be a critical success factor in assigning the appropriate procedure codes. Recognizing that there are some significant differences between ICD-9 and ICD-10 coding guidelines and conventions will be required for coding professionals to apply the appropriate code assignments. Obtaining formal ICD-10 training is a necessary step in learning the coding process; however, applying this knowledge with critical decision-making skills will make you the “top of the muffin.”

About the Author

John Pitsikoulis, RHIA, is the ICD-10 practice leader for Nuance Communications and is an AHIMA-Approved ICD-10-CM/PCS Trainer. John has more than 28 years of management and consulting experience with operational, financial and compliance expertise delivering services and products to healthcare providers. Ares of expertise include ICD-10, coding, prospective payment system reimbursement, clinical documentation, compliance and EMR optimization.

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