2024 ICD-10-CM Diagnosis Code D89.40

Mast cell activation, unspecified

ICD-10-CM Code:
D89.40
ICD-10 Code for:
Mast cell activation, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

Code Classification

  • Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
    (D50–D89)
    • Certain disorders involving the immune mechanism
      (D80-D89)
      • Other disorders involving the immune mechanism, not elsewhere classified
        (D89)

D89.40 is a billable diagnosis code used to specify a medical diagnosis of mast cell activation, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

Unspecified diagnosis codes like D89.40 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Anaphylaxis due to mast cell disorder
  • Mast cell activation syndrome

Clinical Classification

Clinical Information

  • Mast Cell Activation Syndrome

    a clinically and genetically heterogeneous group of mast cell disorders in which there is aberrant release of mast cell mediators with little to no accompanying proliferation of mast cells.
  • Mast Cells

    granulated cells that are found in almost all tissues, most abundantly in the skin and the gastrointestinal tract. like the basophils, mast cells contain large amounts of histamine and heparin. unlike basophils, mast cells normally remain in the tissues and do not circulate in the blood. mast cells, derived from the bone marrow stem cells, are regulated by the stem cell factor.

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.


Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Mast cell activation disorder, unspecified
  • Mast cell activation syndrome, NOS

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).

Replacement Code

D8940 replaces the following previously assigned ICD-10-CM code(s):

  • D89.89 - Oth disrd involving the immune mechanism, NEC

Convert D89.40 to ICD-9-CM

  • ICD-9-CM Code: 279.8 - Immune mechanism dis NEC
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

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

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.