Injury, poisoning and certain other consequences of external causes

• Injuries are grouped by body part rather than category of injury as they were in ICD-9-CM.
• Laterality is specified in this chapter.
• ICD-10-CM introduces a 7th character requirement that describes the type of encounter. Most categories in this chapter use the 7th character requirement. Most categories in this chapter (see below for fractures) have three 7th character values of:
  A - Initial encounter
  D - Subsequent encounter
  S - Sequela
  For traumatic fractures, there are additional 7th character requirements depending upon the type of fracture, and complication. Some of these character descriptions are based on the Gustilo open fracture classification.
• Codes for underdosing are new in ICD-10-CM. Underdosing refers to taking less of a medication than is prescribed by a provider or less than the manufacturer’s instructions. Codes for underdosing should not be assigned as principal or first-listed codes.

Includes:

The word 'Includes' appears immediately under certain categories to further define, or give examples of, the content of the category.

Excludes Notes:

The ICD-10-CM has two types of excludes notes. Each note has a different definition for use but they are both similar in that they indicate that codes excluded from each other are independent of each other.

Excludes Notes:

The ICD-10-CM has two types of excludes notes. Each note has a different definition for use but they are both similar in that they indicate that codes excluded from each other are independent of each other.

Excludes1:

A type 1 Excludes note is a pure excludes. It means 'NOT CODED HERE!' An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

Excludes2:

A type 2 excludes note represents 'Not included here'. An excludes2 note indicates that the condition excluded is not part of the condition it is excluded from but a patient may have both conditions at the same time. When an Excludes2 note appears under a code it is acceptable to use both the code and the excluded code together.

Code First/Use Additional Code notes (etiology/manifestation paired codes)

Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists there is a 'use additional code' note at the etiology code, and a 'code first' note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.

In most cases the manifestation codes will have in the code title, 'in diseases classified elsewhere.' Codes with this title are a component of the etiology/ manifestation convention. The code title indicates that it is a manifestation code. 'In diseases classified elsewhere' codes are never permitted to be used as first listed or principal diagnosis codes. They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition.

Code Also

A code also note instructs that 2 codes may be required to fully describe a condition but the sequencing of the two codes is discretionary, depending on the severity of the conditions and the reason for the encounter.

7th characters and placeholder X

For codes less than 6 characters that require a 7th character a placeholder X should be assigned for all characters less than 6. The 7th character must always be the 7th character of a code