Version 2024

2024 ICD-10-CM Diagnosis Code C91.6

Prolymphocytic leukemia of T-cell type

ICD-10-CM Code:
C91.6
ICD-10 Code for:
Prolymphocytic leukemia of T-cell type
Is Billable?
Not Valid for Submission
Code Navigator:

Code Classification

  • Neoplasms
    (C00–D49)
    • Malignant neoplasms of lymphoid, hematopoietic and related tissue
      (C81-C96)
      • Lymphoid leukemia
        (C91)

C91.6 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of prolymphocytic leukemia of t-cell type. 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 Prolymphocytic leukemia of T-cell type

Non-specific codes like C91.6 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 prolymphocytic leukemia of t-cell type:

  • Use C91.60 for Prolymphocytic leukemia of T-cell type not having achieved remission - BILLABLE CODE

  • Use C91.61 for Prolymphocytic leukemia of T-cell type, in remission - BILLABLE CODE

  • Use C91.62 for Prolymphocytic leukemia of T-cell type, in relapse - BILLABLE CODE

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Patient Education


Chronic Lymphocytic Leukemia

What is leukemia?

Leukemia is a term for cancers of the blood cells. Leukemia starts in blood-forming tissues such as the bone marrow. Your bone marrow makes the cells which will develop into white blood cells, red blood cells, and platelets. Each type of cell has a different job:

  • White blood cells help your body fight infection
  • Red blood cells deliver oxygen from your lungs to your tissues and organs
  • Platelets help form clots to stop bleeding

When you have leukemia, your bone marrow makes large numbers of abnormal cells. This problem most often happens with white blood cells. These abnormal cells build up in your bone marrow and blood. They crowd out the healthy blood cells and make it hard for your cells and blood to do their work.

What is chronic lymphocytic leukemia (CLL)?

Chronic lymphocytic leukemia (CLL) is a type of chronic leukemia. "Chronic" means that the leukemia usually gets worse slowly. In CLL, the bone marrow makes abnormal lymphocytes (a type of white blood cell). When the abnormal cells crowd out the healthy cells, it can lead to infection, anemia, and easy bleeding. The abnormal cells can also spread outside the blood to other parts of the body. CLL is one of the most common types of leukemia in adults. It often occurs during or after middle age. It is rare in children.

What causes chronic lymphocytic leukemia (CLL)?

CLL happens when there are changes in the genetic material (DNA) in bone marrow cells. The cause of these genetic changes is unknown, so it's hard to predict who might get CLL. There are a few factors that might raise your risk.

Who is at risk for chronic lymphocytic leukemia (CLL)?

It is hard to predict who will get CLL. There are a few factors that could raise your risk:

  • Age - your risk goes up as you get older. Most people who are diagnosed with CLL are over 50.
  • Family history of CLL and other blood and bone marrow diseases
  • Racial/ethnic group - CLL is more common in whites than in people from other racial or ethnic groups
  • Exposure to certain chemicals, including Agent Orange, a chemical that was used in the Vietnam War

What are the symptoms of chronic lymphocytic leukemia (CLL)?

In the beginning, CLL does not cause any symptoms. Later, you can have symptoms such as:

  • Swollen lymph nodes - you may notice them as painless lumps in the neck, underarm, stomach, or groin
  • Weakness or feeling tired
  • Pain or a feeling of fullness below the ribs
  • Fever and infection
  • Easy bruising or bleeding
  • Petechiae, which are tiny red dots under the skin. They are caused by bleeding.
  • Weight loss for no known reason
  • Drenching night sweats

How is chronic lymphocytic leukemia (CLL) diagnosed?

Your health care provider may use many tools to diagnose CLL:

  • A physical exam
  • A medical history
  • Blood tests, such as a complete blood count (CBC) with differential and blood chemistry tests. Blood chemistry tests measure different substances in the blood, including electrolytes, fats, proteins, glucose (sugar), and enzymes. Specific blood chemistry tests include a basic metabolic panel (BMP), a comprehensive metabolic panel (CMP), kidney function tests, liver function tests, and an electrolyte panel.
  • Flow cytometry tests, which check for leukemia cells and identify which type of leukemia it is. The tests can be done on blood, bone marrow, or other tissue.
  • Genetic tests to look for gene and chromosome changes

If you are diagnosed with CLL, you may have additional tests to see whether the cancer has spread. These include imaging tests and bone marrow tests.

What are the treatments for chronic lymphocytic leukemia (CLL)?

Treatments for CLL include:

  • Watchful waiting, which means that you don't get treatment right away. Your health care provider regularly checks to see if your signs or symptoms appear or change.
  • Targeted therapy, which uses drugs or other substances that attack specific cancer cells with less harm to normal cells.
  • Chemotherapy
  • Radiation therapy
  • Immunotherapy
  • Chemotherapy with bone marrow or stem cell transplant

The goals of treatment are to slow the growth of the leukemia cells and to give you long periods of remission. Remission means that the signs and symptoms of cancer are reduced or have disappeared. The CLL may come back after remission, and you may need more treatment.

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.