Underdosing of antineoplastic and immunosup drugs, subs

This code indicates that a patient is receiving less than the prescribed or recommended dosage of medications used to treat cancer or suppress the immune system, and this is not the initial encounter for this issue. It signifies that the underdosing is an ongoing problem or a complication being managed during a follow-up visit.

This code is appropriate when a patient on antineoplastic or immunosuppressive therapy is documented as receiving an insufficient dose, and the encounter is for continued management, monitoring, or treatment related to this underdosing. This could include situations where a patient is non-compliant with their medication regimen, or where a physician has intentionally reduced the dose due to adverse effects, but the underdosing is still considered a factor in the patient's care.

• Always sequence this code after the primary diagnosis for which the antineoplastic or immunosuppressive drug is prescribed.
• Ensure documentation clearly supports that the underdosing is an ongoing issue being addressed, not a new problem.
• Distinguish from initial encounter (A), subsequent encounter (D), and sequela (S) based on the patient's treatment phase.