Clarifying Coding for HIV and AIDS in ICD-10

Tune in to this monthly online coding column, facilitated by AHIMA’s coding experts, to learn about challenging areas and documentation opportunities for ICD-10-CM/PCS.

By Elena Miller, MPH, RHIA, CCS

While many people have heard the term “HIV” before, fewer are likely to know what it stands for: human immunodeficiency virus. This is the virus that causes human immunodeficiency virus disease, also known as AIDS. The difference in code assignment is based on whether or not the patient has the disease or if the patient is only a carrier of the virus. Do not get caught up on the terminology of “asymptomatic” vs. “symptomatic,” as many physicians do not utilize those terms when documenting HIV/AIDS. This terminology seems to be causing a great deal of confusion in ICD-10, even though it was also listed in ICD-9.

So what does it even mean? Asymptomatic and symptomatic actually refer to stages in the disease process. Coding professionals should not assume the stage based on “symptoms/conditions” documented or not documented in the record. The physician needs to specify the stage or document the cause and effect relationship with “symptoms/conditions” in the record.

So how are codes assigned for HIV and AIDS diagnoses?

B20 – Human immunodeficiency virus [HIV] disease

  • HIV disease
  • AIDS
  • AIDS – related complex [ARC]
  • AIDS – related conditions
  • HIV infection, symptomatic

Z21 – Asymptomatic human immunodeficiency virus [HIV] infection status

  • HIV infection
  • HIV positive
  • HIV
  • Known HIV
  • HIV virus
  • HIV status
  • HIV test positive
  • HIV infection, asymptomatic


Notice that both of the code descriptions include “human immunodeficiency virus [HIV],” but disease is only included in B20 and infection is only included in Z21. Take for example a case in which the physician documented “HIV disease” throughout the record, and the patient had been admitted for an unrelated reason. The coder feels that the HIV disease should code to Z21 because there were no symptoms mentioned in the record. The coder points out that there is an excludes note under B20 which excludes “asymptomatic human immunodeficiency virus [HIV] infection status.”

That rationale is incorrect. The code description for B20 is human immunodeficiency virus disease, therefore HIV disease is included in B20, according to the Official Guidelines for Coding and Reporting. That excludes note is specifically referring to a patient that has an asymptomatic HIV infection status, also known as HIV positive.

One of the major issues facing coders is that the patient’s condition is documented in a variety of ways within the same record. One day it will be HIV infection, the next will be HIV virus with a history of AIDS, etc. Conflicting documentation needs to be confirmed through a physician documentation clarification (PDC). When writing the PDC, do not include asymptomatic or symptomatic in the multiple choice options, unless the physician has used that terminology in the record. This terminology can be just as confusing for some physicians as it can for coding professionals. Take for example a physician who responds to a query with “asymptomatic HIV AIDS”.

A PDC written to clarify the status of disease should include the following options:

  • HIV positive status only
  • AIDS
  • Other
  • Clinically unable to determine


Please note that a “yes/no” query may be more appropriate depending on the documentation. For example, both HIV infection and oral thrush are documented in the record. It would be appropriate to send a yes/no query to establish a cause-and-effect relationship. Another example would be if the physicians are using HIV positive and AIDS interchangeably in the record. As both conditions are documented, it would be appropriate to use a yes/no query to resolve conflicting documentation between providers.

Elena Miller is director, coding audit and education, at Carolinas Healthcare System.

Submit a Comment

Your email address will not be published. Required fields are marked *

Share This

Share This

Share this post with your friends!