Red pen on virology form ordering HIV tests
Blog September 17, 2018

By Daniel Caillouet, CCS, CPC

Assigning Codes for HIV / AIDS

Assigning HIV/AIDS codes is a sensitive matter and can potentially have great impact on the patient’s life. A patient can be presented with challenges such as denial and/or cancellation of Life and Health insurance for example, and many other possibilities. Once codes have been submitted to payors, it is virtually impossible to have them removed or corrected. As such HIM professionals should take great care to fully understand the guidelines and report these codes appropriately.

One of the most common misunderstandings for assigning ICD-10-CM code B20 HIV is when a patient is diagnosed with HIV, is noted to be prescribed antiviral maintenance medication (regiments such as HAART) and is being evaluated with CD4 counts. In these instances, there is no documentation of an HIV related illness or the specific documentation of the term “AIDS”. These encounters should be coded to Z21 Asymptomatic HIV. The confusion appears to stem from a coder’s practice of referencing the medication list to validate that the chronic conditions documented are still current, however this practice does not apply in this scenario. Consider that the maintenance medication is actually a “prophylactic” therapy and therefore not a criteria for assigning B20 vs Z21.

To properly assign the correct code, we need to adhere to the direction defined in the Official Guidelines for Coding and Reporting Section I.C.1.a.2.d – “Z21, Asymptomatic human immunodeficiency virus [HIV] infection status, is to be applied when the patient without any documentation of symptoms is listed as being ‘HIV positive’, ‘known HIV’, ‘HIV test positive’, or similar terminology.” It also goes on to state –“Do no use this code if the term ‘AIDS’ is used or if the patient is treated for any HIV-related illness or is described as having any condition(s) resulting from his/her HIV positive status; use B20 in these cases.”  This Guideline clearly defines the criteria for assigning B20:

1) an HIV related condition needs to be documented or

2) a direct statement of the term AIDS needs to be documented.

One additional caveat for assigning Z21 pertains to the State of California. Guidance set forth in California’s OSHPD (Office of Statewide Health Planning and Development) states: California Health and Safety code prohibits the disclosure of any HIV test results without the patient’s written authorization for each disclosure. OSHPD’s warning edits are designed to protect health facilities from liability if these codes are inadvertently reported to OSHPD. Due to this guidance, facilities in the state of California have adopted a policy to omit the use of Z21. If the patient does not have an HIV related condition or documentation stating “AIDS”, then no code is reported.

Knowledge is the best tool HIM professionals can use in our daily work. The more we know and understand, the better service we can provide. The codes that an HIM professional assigns to each encounter has a significant impact to the Mid Revenue Cycle, CDI, Case Management and data collection (registries). Most important is that every chart coded represents a person’s life and the codes assigned directly affect the patient personally. As such, HIM professionals should utilize all the resources available to them and code each account as if it were their own.

ICD-10-CM Official Guidelines for Coding and Reporting can be found at: