Toxic effect of carb monx from unsp source, undet, subs

This code signifies a toxic reaction to carbon monoxide where the source of exposure is unknown, and the intent (accidental, intentional self-harm, assault) cannot be determined. It is used for encounters following the initial treatment of the carbon monoxide poisoning.

Apply this code when a patient presents for follow-up care, rehabilitation, or management of residual effects from carbon monoxide poisoning, and the original source of exposure was not identified or documented. This includes situations where the patient's history or circumstances do not clearly indicate how the exposure occurred.

• Ensure documentation clearly states "undetermined" intent and "unspecified source" for carbon monoxide exposure.
• Only use this "subsequent encounter" seventh character (D) for follow-up care after the acute phase of treatment.
• Always sequence this code after any codes for specific manifestations or sequelae of the carbon monoxide poisoning.