What are the principal and secondary ICD-10-CM codes for a patient with acute appendicitis who is also HIV positive?

• A. K35.80; Z21
• B. K35.80; F73
• C. Z21; E16.2
• D. Z21; K35.80

Answer: (A)

In this scenario, the correct coding involves determining the primary diagnosis and the secondary diagnosis based on the patient's condition. Acute appendicitis is classified under the ICD-10-CM code K35.80, which specifically denotes 'Other acute appendicitis.' This code serves as the principal diagnosis because it directly represents the main reason for the patient’s medical encounter.

HIV positive status is classified under the code Z21, which indicates a person living with HIV who is asymptomatic. This code is appropriate as a secondary diagnosis to indicate the patient's chronic condition without current symptoms impacting the acute treatment of appendicitis.

Thus, having K35.80 as the principal code emphasizes the urgent surgical intervention required for appendicitis while Z21 effectively acknowledges the patient's HIV status as relevant for their overall health consideration but not as the primary reason for the visit. This structure of coding aligns with ICD-10-CM guidelines for classifying acute conditions and coexisting chronic conditions effectively.