December 2017

Article by: Valerie M. Slee, RN, BSN, TMS Chair and Susan Jennings, PhD, TMS Research Chair

ICD-10-CM codes for Mast Cell Activation Syndrome (MCAS) were implemented in October 2016 and revised codes for Mastocytosis were implemented in October 2017!

ICD-10-CM Code Proposals for Mast Cell Disorders-Background

Back as far as 2009, TMS was involved in discussions with the American Academy of Allergy, Asthma and Immunology (AAAAI) Mast Cell Disorders Committee about trying to obtain an organized coding hierarchy for mastocytosis and mast cell activation syndrome (MCAS). At the time, we had a solid set of World Health Organization (WHO) diagnostic criteria for mastocytosis, but no such criteria for MCAS. In 2012, a Consensus Committee Proposal for mast cell activation syndrome was published.¹ We finally had a foundation upon which to develop and submit codes for a newly described entity, mast cell activation syndrome. We also prepared to completely revise existing codes for mastocytosis, some of which existed, but which were spread all over the coding manual and lacked important breakdown by subvariant.

For extended periods during 2013 and early 2014, much of our TMS Research Committee time, as well as Valerie’s time as Chair during those years, was spent on this initiative. It was, to say the least, an enormous undertaking. We had the support of the AAAAI Mast Cell Disorders Committee, and from that group of esteemed experts, a sub-committee of volunteers for this project came forward: Arnold Kirshenbaum, MD, Co-Chair; Catherine Weiler, MD, PhD, Co-Chair; Joseph Butterfield, MD; Mariana Castells, MD, PhD; and Cem Akin, MD, PhD. Others volunteered their time and expertise while not being able to commit to serving on the committee. From TMS, we had Susan Jennings, PhD, Research Co-Chair and Chair of TMS efforts on this initiative; Valerie Slee, RN, BSN, TMS Chair; Nancy Russell, PhD, Research Co-Chair; and Mishele Cunningham, RN, BSN, PHN, Education Chair. Numerous phone calls were made to the Centers for Disease Control and Prevention (CDC)/ National Center for Health Statistics (NCHS) even before we began the very complex outline. The first step was gathering all of any existing codes that in any way pertained to a mast cell disorder.  The codes were scattered all over the place, some in rather unexpected categories. From there, we began our comprehensive outline for MCAS, because the CDC/NCHS only invited coding proposals for newly described diseases/disorders at that point in time. We began refining our coding proposal and began working with a physician contact from the CDC/NCHS. We very quickly learned some critical points: that any code previously established or inserted by the WHO would not be deleted completely, and that most codes would include categories called other and/or unspecified. The CDC ICD-10 CM instruction manual describes that codes titled “other” or “other specified” are for use when a patient’s medical record provides detail for which a specific code doesn’t exist. Codes titled “unspecified” are for use when the information in the medical record is insufficient to assign a more specific code. These two categories ended up giving us the flexibility we needed to include future types of MCAS that may arise; indeed, soon after we submitted the coding proposal, data on familial alpha-tryptasemia was published.² For now, medical professionals could potentially use one of these codes to obtain coverage for this diagnosis as needed, until another coding revision occurs.

After developing our outline, we gathered research articles to support each of our coding submissions and its place within the hierarchy we were proposing. We spent hundreds of hours on this work, carefully justifying each code and reviewing our rational with our CDC/HCHS contact.  We learned which place to the right of the decimal point represented what category of disease or symptom. Even though we were only working on MCAS at this point, we made a draft comprehensive outline, inclusive of mastocytosis, in order to ultimately end up with a very cohesive coding hierarchy. We thought that once the codes for MCAS were submitted, proposing the codes for mastocytosis would therefore be a cinch! Boy, were we wrong!

In March 2014, we submitted the coding proposal for MCAS. The codes were implemented in October, 2016, and we were able to announce this during our 2016 TMS Conference in Orlando, Florida! We sure had something to celebrate, because two years of waiting for implementation requires a lot of patience!

Back to March, 2014. Once the codes for MCAS were submitted, we started working on the codes for mastocytosis. This turned out to be much more complex than we thought it would be. Members of the committee wanted to approach this from many different angles. Emails flew back and forth for months. We tried very hard to integrate all of the changes and recommendations that everyone suggested, but as the deadline approached, we just could not make it work. Finally, we called everyone on the coding committee and asked for a 5 PM meeting that day in July, 2014. Everyone agreed, and showed up pretty much on time! This was an amazing feat for busy practicing physician researchers in different time zones with so little notice, and speaks to their dedication. We worked hard as a group for over an hour and finalized the coding document! Once it was approved by the AAAAI Board of Directors, who cosponsored the initiative, we sent it to Joseph Butterfield, MD, who was the Chair at the time of the AAAAI Mast Cell Disorders Committee, and he submitted it on behalf of the committee, TMS and the AAAAI.

Although we were instructed to closely adhere to the WHO classifications for mastocytosis, were told we could not remove an existing code completely, and needed to incorporate the expanded coding requirements of ICD-10-CM, resulting in a large number of codes being proposed. The primary feedback on our mastocytosis coding proposal was related to concern regarding the large number of codes for a rare set of disorders. We asked for specific input on our proposal so we could continue to work on revising the mastocytosis codes, but did not receive any status updates for three years, from July 2014 to October 2017, other than instructions that if the CDC/NCHS needed additional consultation with our committee, they would contact us. We had decided to start from scratch and revise all the codes for mastocytosis, a project we would undertake in 2018. Then, on October 1, 2017, the CDC/NCHS announced the new codes which had been implemented, and among them were new codes for mastocytosis! They accepted many of the coding categories we proposed, but simplified the codes within them tremendously.

This is a huge achievement, and one that all of us on the coding committee are very proud of. Coding for mastocytosis, MCAS and other newly identified mast cell diseases may require some revision, or even new coding proposals in the future, but overall we now have very workable codes. These codes facilitate patients getting insurance coverage, applying for disability, and obtaining the medications they need. They also enhance recognition of these diseases, and increase their credibility.