Major Changes from ICD-9 to ICD-10

In general, most of the changes were of the following types:

  1. 1.   Grouping of codes – Conditions have been grouped in a more logical fashion than in ICD-9.
  2. 2.   More complete descriptions – In ICD-10, the subcategory titles are usually complete so that the coder does not have to read previous codes to understand the meaning of the code. 
  3. 3.   Fifth and sixth characters – Fifth and sixth characters are incorporated into the code listing rather than having common fifth digits listed at the beginning of a chapter, section, or category.
  4. 4.   Laterality ICD-10 incorporates laterality of conditions or injuries at the fifth or sixth character level.
  5. 5.   Increased specificity – ICD-10 offers expanded detail for the various conditions. 
  6. 6.   Excludes notes – There are three kinds of excludes notes that are used in ICD-10.
  7. 7.   Use of extensions – Extensions are used in ICD-10 to provide additional information.  Most often found in the injury codes.
  8. 8.   Combination codes – There are numerous codes in ICD-10 that group etiology and manifestation.  In ICD-9 generally two codes are required.
  9. 9.   Terminology used – Many of the category code or subcategory code titles have been ICD-9, changed to reflect new technology and more recent medical terminology.
  10. 10.               Postprocedural conditions – There are many more codes added to ICD-10 to describe postoperative or postprocedural conditions.

Doctors, third-party payers and coders will need to be more aware of what documentation is needed to correctly assign codes and trained in the use of the new classification system.