2024 ICD-10-CM Diagnosis Code D89.42

Idiopathic mast cell activation syndrome

ICD-10-CM Code:
D89.42
ICD-10 Code for:
Idiopathic mast cell activation syndrome
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)

D89.42 is a billable diagnosis code used to specify a medical diagnosis of idiopathic mast cell activation syndrome. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

Approximate Synonyms

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

  • Idiopathic mast cell activation syndrome

Clinical Classification

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

D8942 replaces the following previously assigned ICD-10-CM code(s):

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

Convert D89.42 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.