If the United States is the last country to implement ICD-10, why are there so many unanswered coding questions and why do we have to wait for Coding Clinic advice?
While it seems logical that someone would have figured out all of this ICD-10 stuff within the last 20 years as we've been "messing around" here in the US (please note the sarcasm, because I don't really think we've been messing around; we've actually been quite busy), the reality of the situation is that the US version of ICD-10 is different from everyone else's. The core ICD-10 code set was developed by the World Health Organization (WHO) and classifies causes of morbidity (i.e., diagnoses) and every country has the ability to adapt it further (e.g., ICD-10-CA in Canada, ICD-10-AM in Australia, ICD-10-CM in the US). Two things should have jumped out at you based on this statement:
- ICD-10 diagnosis codes may be different in Canada, Australia, and the US
- The international code set does not include procedures
Let's tackle #1 first. The US version of the ICD-10 diagnosis codes, ICD-10-CM, is a clinical modification (BTW - that's what the "CM" stands for; it's not "coding manual" like some people seem to think). It is based on the WHO version, but has been adapted for use here in the good ole United States of America. I haven't had a ton of time to compare it to the original, but what I do know about the CM version is this:
- The Excludes1/Excludes2 convention, which solves a lot of problems from ICD-9 (and creates a few new ones) is not part of the WHO version
- The use of 7th character extensions for injuries and poisonings is not part of the WHO version
- The expansion of the external cause codes, which are not required for reporting, are not nearly as extensive in the WHO version
- While we have adapted diabetes terminology in the US to Type 1 and Type 2 diabetes, the WHO version still uses the insulin-dependent diabetes mellitus (IDDM) and noninsulin-dependent diabetes mellitus (NIDDM) terminology that we've worked so hard to banish from our medical record documentation here in the States
Most of the really hard diagnosis questions I get about coding ICD-10 diagnoses revolve around the changes that are unique to the CM version.
As for the procedural component, ICD-10-PCS (which stands for procedure coding system), that was developed in the US by CMS under contract with 3M. Although I've heard that other countries have plans to adopt PCS, right now the US is the only country using it. Although other countries have procedural coding systems, it's important to remember that we are the only ones using coding for reimbursement. For that reason, we will likely place more weight on those procedure codes than other countries and when it comes to PCS, it's uncharted territory.
Hopefully that answers a couple of questions about the ambiguity of ICD-10. And may I also just point out that this is nothing new. Coding has always undergone an evolutionary process. We have seen it with ICD-9-CM and CPT. It's the reason we have official publications like the Coding Clinic and CPT Assistant. If you are not familiar with these publications, you need to be. They are official resources that answer a lot of questions. And as of second quarter of this year, the American Hospital Association has stopped publishing Coding Clinic for ICD-9-CM and is only publishing Coding Clinic for ICD-10-CM/PCS. My colleagues and I have been monitoring the publication very carefully each quarter because their advice does change some previous assumptions many have made based on what we know about these new coding systems.
