Immunodeficiency Status Codes

New codes were created in October 2020 to report specific causes for a patient’s immunocompromised state. Previously, there was no way to capture a patient who was immunocompromised or immunodeficient. The only way was to use the “long-term use of drugs” and/or the conditions related to the immunocompromised state.


So what does it mean when a patient is immunocompromised or immunodeficient?


An immunocompromised state refers to the weakened condition of an individual’s immune system that makes it less able to fight infections and other diseases. When the immune system fails to respond adequately to infection, it’s called an immunodeficiency, and the patient may become immunocompromised.

Treating a patient who is immunocompromised poses more risks and challenges; therefore, it is important to identify a patient with this status whether coding hospital Inpatient/Outpatient or Physician Office records.

Why is this important for coding? 

The new D codes below are all Complications/Comorbidities (CCs) that will impact the MS-DRG for inpatient reimbursement. And they also have an effect on Risk Adjustment Scores for Medicare Advantage patients since these codes are CMS-HCCs (Hierarchical Condition Categories).

Multiple codes may be assigned to show immunodeficiency due to multiple causes (e.g., cancer and antineoplastic medication). In cases where the cause of the immunosuppression is not clearly documented, query the provider.

D84.821 Immunodeficiency due to drugs

Immunodeficiency due to medications that interfere with the immune system. These medications include but are not limited to immunosuppressants, corticosteroids and chemotherapy.

D84.822  Immunodeficiency due to external causes

Immunodeficiency caused by external factors such as exposure to radiation therapy or due to bone marrow transplant.

D84.81 Immunodeficiency due to conditions classified elsewhere

Created for an immunocompromised state due to a specific medical condition such as HIV, AIDS*,(See explanation below) certain cancers and genetic disorders that are classified elsewhere in ICD-10-CM.

D84.89 Other immunodeficiencies

*There was an update in the First Quarter 2021 Coding Clinic that clarified the use of D84.81.  “It is not appropriate to assign code D84.81, Immunodeficiency due to conditions classified elsewhere, together with code B20, human immunodeficiency virus (HIV) disease. Immunocompromise/immunodeficiency is part of the clinical picture in HIV disease, and code B20 captures fully the immunocompromised state.” Fortunately, there is an Excludes1 note under code D84.81, excluding B20, confirming that HIV/AIDS is not coded here.

Here are some examples of the new Immunodeficiency Status codes in practical use directly from Coding Clinic:


A patient was seen in the emergency department for cellulitis of two fingers on her right hand. She was admitted to start intravenous antibiotics due to having an immunocompromised state caused by immunosuppressant medication that she takes for systemic lupus erythematosus (SLE). What are the appropriate code assignments for the admission?


Assign code L03.011, Cellulitis of the right finger, as the principal diagnosis. Assign codes M32.9, Systemic lupus erythematosus, unspecified, for SLE, D84.821, Immunodeficiency due to drugs, and Z79.899, Other long-term (current) drug therapy, for the patient’s immunosuppressed state due to long-term use of immunosuppressants.

In this case, the immunosuppressant medication was prescribed by the provider to suppress the patient’s immune system. An adverse effect code is not assigned when the medication has achieved its intended result in lowering the patient’s immune response to systemic lupus erythematosus.



A patient with multiple myeloma was seen for ear pain and cold symptoms due to acute otitis media of the left ear and acute viral bronchitis. The provider documented that the patient is immunosuppressed due to current long-term chemotherapy. What are the appropriate code assignments for this encounter?


Sequence either code J20.8, Acute bronchitis due to other specified organisms, or code H66.92, Otitis media, unspecified, left ear, as the first-listed diagnosis. Assign codes D84.821, Immunodeficiency due to drugs, for the patient’s immunosuppressed state as a result of chemotherapy, and T45.1X5A, Adverse effect of antineoplastic and immunosuppressive drugs, initial encounter. In this case, immune suppression is not part of the intended effect of the antineoplastic drugs and is coded as an adverse effect. Additionally, assign codes C90.00, Multiple myeloma not having achieved remission, for the multiple myeloma and Z79.899, Other long term (current) drug therapy, for the chemotherapy.


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