Version 2024

2024 ICD-10-CM Diagnosis Code Z51.1

Encounter for antineoplastic chemotherapy and immunotherapy

ICD-10-CM Code:
Z51.1
ICD-10 Code for:
Encounter for antineoplastic chemotherapy and immunotherapy
Is Billable?
Not Valid for Submission
Code Navigator:

Code Classification

  • Factors influencing health status and contact with health services
    (Z00–Z99)
    • Encounters for other specific health care
      (Z40-Z53)
      • Encounter for other aftercare and medical care
        (Z51)

Z51.1 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of encounter for antineoplastic chemotherapy and immunotherapy. The code is not specific and is NOT valid for the year 2024 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Encounter for antineoplastic chemotherapy and immunotherapy

Non-specific codes like Z51.1 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for encounter for antineoplastic chemotherapy and immunotherapy:

  • Use Z51.11 for Encounter for antineoplastic chemotherapy - BILLABLE CODE

  • Use Z51.12 for Encounter for antineoplastic immunotherapy - BILLABLE CODE

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Type 2 Excludes

Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
  • encounter for chemotherapy and immunotherapy for nonneoplastic condition - code to condition

Patient Education


Cancer Chemotherapy

What is cancer chemotherapy?

Cancer chemotherapy is a type of cancer treatment. It uses medicines to destroy cancer cells.

Normally, the cells in your body grow and die in a controlled way. Cancer cells keep growing without control. Chemotherapy works by killing the cancer cells, stopping them from spreading, or slowing their growth.

Chemotherapy is used to:

  • Treat cancer by curing the cancer, lessening the chance it will return, or stopping or slowing its growth.
  • Ease cancer symptoms by shrinking tumors that are causing pain and other problems.

What are the side effects of chemotherapy?

Chemotherapy does not just destroy cancer cells. It can also harm some healthy cells, which causes side effects.

You may have a lot of side effects, some side effects, or none at all. It depends on the type and amount of chemotherapy you get and how your body reacts.

Some common side effects are:

  • Mouth sores
  • Fatigue
  • Nausea and vomiting
  • Pain
  • Hair loss

There are ways to prevent or control some side effects. Talk with your health care provider about how to manage them. Healthy cells usually recover after chemotherapy is over, so most side effects gradually go away.

What can I expect when getting chemotherapy?

You may get chemotherapy in a hospital or at home, a doctor's office, or a medical clinic. You might be given the medicines by mouth, in a shot, as a cream, through a catheter, or intravenously (by IV).

Your treatment plan will depend on the type of cancer you have, which chemotherapy medicines are used, the treatment goals, and how your body responds to the medicines.

Chemotherapy may be given alone or with other treatments. You may get treatment every day, every week, or every month. You may have breaks between treatments so that your body has a chance to build new healthy cells.

NIH: National Cancer Institute


[Learn More in MedlinePlus]

Cancer Immunotherapy

Immunotherapy is a cancer treatment that helps your immune system fight cancer. It is a type of biological therapy. Biological therapy uses substances that are made from living organisms, or versions of these substances that are made in a lab.

Doctors don't yet use immunotherapy as often as other cancer treatments, such as surgery, chemotherapy, and radiation therapy. But they do use immunotherapy for some types of cancer, and researchers are doing clinical trials to see whether it also works for other types.

When you have cancer, some of your cells begin to multiply without stopping. They spread into the surrounding tissues. One reason that the cancer cells can keep growing and spreading is that they are able to hide from your immune system. Some immunotherapies can "mark" your cancer cells. This makes it easier for your immune system to find and destroy the cells. It is a type of targeted therapy, which uses drugs or other substances that attack specific cancer cells with less harm to normal cells. Other types of immunotherapies work by boosting your immune system to work better against cancer.

You could get immunotherapy intravenously (by IV), in pills or capsules, or in a cream for your skin. For bladder cancer, they might place it directly into your bladder. You may have treatment every day, week, or month. Some immunotherapies are given in cycles. It depends on your type of cancer, how advanced it is, the type of immunotherapy you get, and how well it is working.

You may have side effects. The most common side effects are skin reactions at the needle site, if you get it by IV. Other side effects may include flu-like symptoms, or rarely, severe reactions.

NIH: National Cancer Institute


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.