Underdosing of immunoglobulin, initial encounter

This code indicates that a patient has received an insufficient amount of immunoglobulin, leading to a suboptimal therapeutic effect or a failure to achieve the intended prophylactic benefit. This underdosing can result from various factors, such as incorrect dosage calculation, patient non-adherence, or issues with administration.

This code is appropriate when documenting the initial presentation or diagnosis of a patient experiencing adverse effects or treatment failure directly attributable to receiving less than the prescribed or clinically indicated dose of immunoglobulin. This includes situations where the patient's condition worsens or does not improve as expected due to the insufficient administration of the medication.

• Always assign an additional code for the specific adverse effect or condition being treated or prevented by the immunoglobulin.
• Ensure documentation clearly supports that the underdosing is the cause of the current clinical issue.
• Distinguish this from medication non-compliance (Z91.1xx) if the underdosing is due to a systemic issue rather than patient refusal.