Chapter-Specific Guidelines: Injury, External Causes, and Factors – Key Terms

The encounter where the patient receives active treatment for an injury; may span multiple visits during active treatment phase. Encounter for routine care during the healing/recovery phase after active treatment has been completed. Late effect or complication arising after the acute injury has healed; residual condition coded first, injury code with S follows. Unintended reaction to a correctly administered substance; manifestation coded first, followed by the adverse effect code. Reaction to incorrect substance, wrong dose, or improper use of a drug or chemical; poisoning code sequenced first. Taking less medication than prescribed; the resulting worsened condition is coded first, followed by the underdosing code. Chapter 20 codes (V00–Y99) that describe how, where, and under what circumstances an injury or adverse effect occurred. Z code identifying the location where the injury occurred (e.g., home, school, street). A fracture where the bone pierces the skin or is exposed to the external environment; specified by type (I, II, IIIA–C). Method for estimating burn extent as a percentage of total body surface area; T31.– codes capture TBSA burned.