Grab a photograph. Any photo. Then take it to a photocopier, and copy it.
Call that copy an ICD-9 code. Then take that copy (the one called "ICD-9 code") and copy it on the same photocopier. That copy of a copy is called an ICD-10 code.
How does it look?
Not great. Making a copy of a copy is less than desirable. You lose a lot of information that way.
Which helps explain what happened when University of Illinois Chicago researchers studied what happened when they applied a web-based ICD-10 converter to a bunch of ICD-9 codes.
To get an idea of how challenging the ICD-10 transition will be, researchers chose 120 ICD-9 codes from the Illinois Medicaid database used by hematology-oncology physicians. These represented the highest reimbursements. Researchers also used the 100 most-used codes from the University of Illinois Cancer Center.
They then ran the ICD-9 codes through a conversion tool developed at the University of Illinois Chicago to get ICD-10 codes. That yielded the following results:
"The transition to ICD-10-CM led to significant information loss, affecting 8% of total Medicaid codes and 1% of UICC codes; 39 ICD-9-CM codes with information loss accounted for 2.9% of total Medicaid reimbursements and 5.3% of UICC billing charges."
Coding experts have been saying from the start that conversion and mapping tools are a bad way to generate ICD-10 codes. The crosswalks have very few direct translations. For the most part, they give users many codes to choose. Someone still needs to refer to the documentation and use judgment to choose the right code.
Canadian hospitals found this out when they tried mapping tools to convert ICD-9 codes to ICD-10-CA codes. They found it easier and more complete to learn the ICD-10 codes.