Poisoning by thyroid hormones and substitutes, undet, subs

This code signifies an adverse effect resulting from thyroid hormones or their synthetic replacements, where the intent of the poisoning (e.g., accidental, intentional self-harm, assault) cannot be determined. This diagnosis is used when a patient is receiving follow-up care for such an event.

Apply this code for patients presenting for ongoing management or evaluation of complications stemming from an undetermined poisoning by thyroid medications. This includes scenarios like follow-up appointments after initial stabilization or for monitoring long-term effects. It is appropriate when the initial encounter for the poisoning has already been coded.

• Always assign an additional code for any associated manifestations or complications of the poisoning.
• Do not use this code for initial encounters; instead, select the appropriate initial encounter code (T38.1X1A, T38.1X2A, T38.1X3A, or T38.1X4A).
• Ensure documentation clearly supports the "undetermined" intent and that this is a subsequent encounter.