What code is used when a patient tests positive for HIV and is symptomatic?

The correct choice, B20, is the appropriate code for a patient who tests positive for HIV and exhibits symptoms. This code specifically designates "Human immunodeficiency virus [HIV] disease," which encompasses symptomatic HIV infection, including any AIDS-related conditions. In the context of ICD-10-CM, this coding reflects the clinical significance of the diagnosis, indicating that the patient is not merely a carrier of the virus but is experiencing adverse health effects due to it.

The other codes listed relate to different medical situations, thereby making them unsuitable for this scenario. M00.9 refers to unspecified infectious arthropathy, which does not connect to HIV. R65.2 is related to severe sepsis with septic shock but is not specific to HIV. A41.9 addresses unspecified sepsis, which again, does not capture the nuances of an HIV positive status with symptomatic disease. Therefore, B20 distinctly identifies the patient’s HIV-related health status, which is pivotal in ensuring accurate diagnosis and treatment planning.