Cracking the Code
HIV coding contains some of the most challenging rules in the ICD-10-CM guidelines. It is very important that coders and auditors not only understand the guidelines but also understand the pathophysiology of the disease.
According to the CDC, “HIV (human immunodeficiency virus) is a virus that attacks the body’s immune system. If HIV is not treated, it can lead to AIDS. There is currently no effective cure. Once people get HIV, they have it for life. But with proper medical care, HIV can be controlled. People with HIV who get effective HIV treatment can live long, healthy lives and protect their partners.”
There are a few things to consider when selecting the proper code for HIV. Is the patient asymptomatic, or known to have had an HIV-related condition in the past? What is the purpose of the admission or encounter? There are specific sequencing rules to follow when the patient is being treated for an HIV-related condition versus a non-HIV-related condition (e.g., injury from a fall).
When we follow our ICD-10-CM guidelines to I.C.1.a.1, we read that HIV infection/illness is coded only for confirmed cases. Confirmation does not require documentation of a positive blood test or culture for HIV; the physician’s diagnostic statement that the patient is symptomatic or has an HIV-related illness is sufficient. Statements such as “HIV positive,” “known HIV,” “HIV test positive,” or similar wording should be coded to Z21 Asymptomatic HIV infection status, per Coding Clinic, Q1 2019.
ICD-10-CM guideline I.C.1.a.2 states the proper sequencing for HIV depends on the reason for the admission or encounter. When a patient is admitted for an HIV-related condition, B20 is sequenced first, followed by additional diagnosis codes for all reported HIV-related conditions. Now, if a patient with HIV disease is admitted for an unrelated condition (fracture), the code for the unrelated condition is sequenced first. Code B20 is reported as an additional diagnosis, as are any HIV-related conditions.
When we follow the ICD-10-CM guidelines to I.C.1.a.2.d, Z21 Asymptomatic HIV infection status is applied when the patient is HIV positive and does not have any documented symptoms of an HIV-related illness. Do not use this code if the term AIDS is used. If the patient is treated for any HIV-related illness or is described as having any condition resulting from HIV-positive status as stated by the physician, use B20.
A known prior diagnosis of an HIV-related illness should be coded to B20. After the patient has developed an HIV-related illness, the patient’s condition should be assigned code B20 on every subsequent admission/encounter. It is important to remember not to assign R75 or Z21 to a patient with an earlier diagnosis of AIDS or symptomatic HIV.
ICD-10-CM guideline I.C.1.a.2.g states an HIV infection status during pregnancy, childbirth, or the puerperium should be reported using the codes from subcategory O98.7- HIV disease complicating pregnancy, childbirth, and the puerperium. This should be followed by either Z21 when the patient is asymptomatic with no history of an HIV-related illness, or if the patient has had an HIV-related illness in the past, B20, the code for the HIV-related illness. Finally, a code from Z3A for the weeks of gestation should also be reported. Remember, codes from ICD-10-CM chapter 15 always take sequencing priority and should be listed first.