How is the ICD-10-CM Code Set Different from ICD-9-CM?

ICD-9 codes have between three and five characters, and with the exception of “V” and “E” codes, are exclusively numeric.  The fourth or fifth character is utilized for greater specificity and combinations of diagnoses are coded separately.  One example is diabetes with polyneuropathy which codes as 250.6x and 357.2.  It would be incorrect to code 250.0x for a diabetic patient with neurological manifestations.  In ICD-10-CM, this diagnosis would be coded as E08.42   Diabetes mellitus due to underlying condition with diabetic polyneuropathy because the new code set introduces combination codes.  When a condition has associated symptoms and/or manifestations, ICD-10 has created one code to encompass several diagnoses.

That ICD-10 code certainly looks different from what we’ve become accustomed to, right?  That’s because ICD-10 makes substantial changes to the appearance of codes.  Although some of the general coding characteristics and categories (called chapters) remain the same, ICD-10 adds some interesting twists:

  • ICD-10 codes have between three and seven characters.
  • ICD-10 codes always begin with an alphabetic character followed by two numeric ones. All alpha characters, except the letter “u,” are included.  (Some codes that contain the letter “I” or “O” followed by a one or zero can appear a little strange, but after some practice, they will seem less so.)
  • The fifth and sixth characters are used for greater specificity, each one increasing the precision of the diagnosis.  Examples are Z67.20  Type B blood, Rh positive and Z67.21  Type B blood, Rh negative.  Some others include: O30.012 Twin pregnancy, monochorionic/monoamniotic, second trimester and L89.022  Pressure ulcer of left elbow, stage 2.
  • The seventh character is called an ‘extension’ and is used to identify the type of encounter or to expand on the nature of the condition (e.g., sequelae, complications, etc.)
  • ICD-10 requires the specification of laterality, which impacts the code selected.  The majority of ICD-10 codes are for the identification of a condition affecting the right, left or bilateral sides.  Examples are: H61.21  Impacted cerumen, right ear and H61.22  Impacted cerumen, left ear, as well as H61.23  Impacted cerumen, bilateral.
  • “X” marks the spot!  ICD-10 uses the placeholder character ‘x’ to occupy one or more spaces in codes where other characters don’t yet exist.  An example is M22.2x2  Patellofemoral disorders, left knee.  Note that laterality is also specified.

General Equivalence Mapping (GEMs) is a system of ‘translation’ that helps to convert an ICD-9 code into ICD-10.  However, GEMs are not considered crosswalks, and it’s dangerous to think they operate like, for example, an English-Spanish dictionary.  Keep in mind that ICD-10 has roughly four times more codes than ICD-9, many of which represent new conditions, more specific aspects of conditions, and combinations of diagnoses/symptoms.  It is best to understand and learn ICD-10’s format and practice using the code set than to rely on shortcuts that will definitely impact your organization’s productivity and profitability.

This entry was posted in Coding & Billing, Home Health, ICD-10, Practice Management and tagged , , , , , , , , , , , , . Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *