Underdosing of unsp drug/meds/biol subst, subs

This code signifies that a patient is experiencing adverse effects or complications due to receiving less than the prescribed or recommended amount of an unspecified medication, drug, or biological substance. This underdosing is not due to a known specific substance, and the encounter represents follow-up care for the initial underdosing event.

Use this code when a patient presents for ongoing management or evaluation of symptoms directly related to an underdosing event where the specific substance involved is not documented. This applies to situations such as a patient not taking enough of their medication, a medication being improperly administered in insufficient quantities, or a biological substance being given below therapeutic levels, and the current visit is for follow-up care.

• Requires a seventh character "D" for subsequent encounter, indicating ongoing care for the underdosing.
• Only use when the specific drug, medicament, or biological substance is unknown or not documented. If known, a more specific T50.- code should be used.
• Always sequence this code after any codes for the specific adverse effects or complications resulting from the underdosing.