What does 'code first' mean and when is it used?

• A. It indicates the underlying condition should be coded last.
• B. It indicates the secondary condition is always primary.
• C. It indicates that codes must be assigned alphabetically.
• D. It indicates the underlying condition must be coded first when another condition is a complication or manifestation.

Answer: (D)

When a condition is a complication or manifestation of another, you start with the underlying condition in the coding sequence. This is the meaning of “code first.” The goal is to show that the primary disease drives the clinical picture, with the related complication or manifestation documented afterward.

So, if there is a condition that arises because of another condition, code the underlying condition first, then code the complication or manifestation. For example, if pneumonia is a complication of influenza, you would code influenza first and then pneumonia. This ordering makes clear that the influenza is the root cause and the pneumonia is the result.

The other options don’t fit because they describe sequencing or rules that aren’t what “code first” conveys: there’s no instruction to code the underlying last, to make a secondary condition primary, or to assign codes alphabetically.