Toxic effect of unspecified substance, undetermined, sequela

This code signifies a long-term or late-onset health problem resulting from exposure to an unknown toxic substance, where the intent (e.g., accidental, intentional self-harm, assault) of the exposure cannot be determined. It indicates that the acute phase of the toxic effect has passed, and the patient is now experiencing residual or chronic manifestations.

Use this code when documenting a sequela (e.g., chronic organ damage, neurological deficits, persistent pain) directly attributable to a past toxic exposure, but the specific substance involved remains unidentified. This code is appropriate when the medical record explicitly states that the intent of the exposure is undetermined.

• Only use this code for sequelae; do not use for acute toxic effects.
• Ensure documentation clearly supports an "undetermined" intent and an "unspecified substance."
• Always seek a more specific code if the toxic substance or intent can be identified.