ICD-10-CM General Guideline

General Coding Guidelines:

1. How to locate code in the ICD 10 CM.

• • First, locate the term in the Alphabetic Index, then verify the code in the Tabular List.
  • A dash (-) at the end of an Alphabetic Index indicates that additional characters are required.

2. Valid and Invalid ICD-10-CM code.

• • ICD-10-CM diagnosis codes are with 3, 4, 5, 6 or 7 characters. Hence it must be reported at their highest number of characters available.
  • Invalid code, if it has not been coded to their highest number of characters required for that code.

3. Signs and symptoms.

• • When there is no confirmed diagnosis, then it is acceptable to report available signs and symptoms.
  • Signs and symptoms that are associated with a disease process should not be assigned as additional codes.
  • Signs and symptoms that are not associated with a disease process may be coded as additional codes.

4. Multiple coding.

• • “Use additional code” – Indicates a secondary code should be added.
  • “Code first” – Indicates another respective code should be coded first.
  • “Code, if applicable, any causal condition first”, notes indicate that this code may be assigned as a principal diagnosis when the causal condition is unknown or not applicable. If a causal condition is known, then the code for that condition should be sequenced as the principal or first-listed diagnosis.

5. Acute and Chronic Conditions

• • If the same condition is described as both acute (subacute) and chronic, then code both and sequence the acute (sub-acute) code first followed by chronic.

6. Combination Code

A combination code is a single code used to classify:

Two diagnoses, or

*A diagnosis with an associated manifestation, or

*A diagnosis with an associated complication.

Combination codes are identified by referring to subterm entries in the Alphabetic Index and by reading the inclusion and exclusion notes in the Tabular List.

When the combination code lacks necessary specificity in describing the manifestation or complication, an additional code should be used as a secondary code.

7. Sequela (Late Effects)

• • A sequela is the residual effect after the acute phase of an illness or injury.
  • There is no specific time limit on when a sequela code can be used.
  • Generally, requires two codes sequenced in the following order,

The condition or nature of the sequela is sequenced first.

The sequela code is sequenced second.

An exception to the above guidelines, where the code for the sequela is followed by a manifestation code identified in the Tabular List and title, or the sequela code has been expanded (at the fourth, fifth or sixth character levels) to include the manifestation(s). The code for the acute phase of an illness or injury that led to the sequela is never used with a code for the late effect.

8. Same Diagnosis Code

• • Each unique ICD-10-CM diagnosis code may be reported only once for an encounter. 

9. Laterality

• • Laterality indicates left, right or is bilateral.
  • If no bilateral code is available and the condition is bilateral, assign separate codes for both the left and right side.
  • If the side is not mentioned in the medical record, assign the unspecified side code.

10.  Unspecified Code 

• • When sufficient clinical information is not known or available about a particular health condition to assign a more specific code, then report the appropriate “unspecified” code.