ICD 10 Training: Difference between ICD9 and ICD 10



ICD-10 facilitates international comparisons of quality care and sharing of best practices globally. Some of the reasons for the change from ICD-9 to ICD-10, ICD-9 is limited in detail. For those of you who are into healthcare coding, you know that sometimes you pick the best applicable code. There isn't always a real specific code for what you have in your documentation.
It is 30 years old. What else in healthcare and computers now is 30 years old? There's not a lot. A lot of changes are taking place and there are more to come.


ICD-9 is outdated and obsolete terminology. A lot of new medical treatments, procedures, et cetera have been created and are being used regularly since ICD-9 was implemented. Its inaccurate and limited data when we can't code real specifically and we use the best selected medical coding option. That of course affects your data and it's inconsistent with current medical practice.


ICD-10, some of the advantages that are different from ICD-9 include greater specificity. ICD-10 allows comparison of mortality and morbidity data and of course that's done worldwide and so we have to be consistent with the other countries when we compare that data. And it's better data for measuring care, for designing payment systems, processing claims and so on. There's a list of items there that are included.

There are two parts to the ICD-9 CM/PCS. The CM is the diagnosis coding which is used for all healthcare settings. It was developed by the Centers for Disease Control and Prevention. It has a different number of digits but the format is similar to ICD-9.


When you start learning this new medical coding system, you pick that up pretty quickly. If you're already an ICD-9 coder, you learn some of the differences that there are many similarities.
In the Procedural Coding System though, the PCS, that's the one that's a little more complicated, the change is major. This was developed by the Centers for Medicare and Medicaid Services for in-patient hospital settings only.
ICD-9 has 14,025 diagnosis codes. ICD-10 diagnosis codes are 68,069. That's quite a difference; a huge increase. And the reason for that is the specificity and all of the new items that are included.


For procedures from ICD-9, they went from 3,824 to 72,589. Again, that's an enormous increase.

How do ICD-9 and ICD-10 differ?

The diagnosis coding has three to five digits in ICD-9. In ICD-10 it will be three to seven digits.
ICD-9, the first digit is alpha or numeric; the only alpha are the E and V codes. And the numeric part can be all-numeric two to five digits.


In ICD-10, digit one is alpha; digits two and three are numeric. Digits four to seven are alpha – not case sensitive – or numeric. So there's quite a combination there compared to what we're used to.
On the procedure codes, the current ICD-9 is three to four digits and they're all numeric. For procedure ICD-10 codes, there are seven digits. They're alpha or numeric.


The letters O and I are not used to avoid confusion with the numbers 0 and 1. So you will see the 0 and 1. Any time you see those, they're 0 and 1; not O and I.

More differences in ICD-10, the code titles are more complete. There's no need to refer back to a category, sub-category or sub-classification to determine the complete meaning of the code. You can use your index but once you learn how to use the book, you have your full description there.

Laterality which means it tells you the specific side of the body that's affected. It has been added to relevant codes.

There's an expanded use of combination codes. Sometimes you don't have to use two or three codes. The entire definition is in one code.

Injuries are grouped by anatomical site rather than by type of injury. That's a big difference.
And ICD 10 diagnosis codes reflect modern medicine and updated medical terminology. And this is where it's really beneficial for coders and anyone involved in this who hasn't taken a medical terminology course for a while or an anatomy and physiology course, a refresher is really helpful.

For instance, combination code I25.110, now this is in CM – it's the I and O that are now used in the procedural coding – atherosclerotic heart disease of native coronary artery with unstable angina pectoris. And so that gives you the entire description. You don't have to piece it together.


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