Toxic effect of unsp gases, fumes and vapors, undet, sequela

This code indicates a long-term health problem or residual effect resulting from exposure to an unknown gas, fume, or vapor, where the intent of the exposure (e.g., accidental, intentional self-harm) cannot be determined. The patient is no longer experiencing the acute toxic effects but is presenting with a sequela directly attributable to the past exposure.

Use this code when a patient presents with a chronic condition or lasting impairment that is documented as a direct consequence of a past exposure to an unspecified gas, fume, or vapor, and the circumstances surrounding the original exposure remain unclear or undocumented. This applies when the acute phase of the poisoning has resolved, and the current encounter is for the management of the residual effects.

• Always sequence this code after the code(s) for the specific sequela being treated.
• Ensure documentation clearly links the current condition to a past toxic exposure of an unspecified gas, fume, or vapor with undetermined intent.
• The "S" in the 7th character indicates sequela; do not use for acute toxic effects.