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ICD-10 Guide
ICD-10 CodesD89.43

D89.43

Billable

Secondary mast cell activation

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 D89.43 is a billable code used to indicate a diagnosis of secondary mast cell activation.

Key Diagnostic Point:

Secondary mast cell activation refers to the pathological activation of mast cells due to underlying conditions such as infections, autoimmune diseases, or malignancies. Mast cells are immune cells that play a crucial role in allergic responses and inflammation. In secondary mast cell activation, these cells become hyper-responsive, leading to the release of mediators such as histamine, cytokines, and other inflammatory substances. This can result in a range of symptoms including flushing, itching, abdominal pain, and anaphylaxis in severe cases. The condition is often associated with hematologic disorders, particularly those that involve dysregulation of the immune system, such as chronic myeloid leukemia or systemic mastocytosis. Accurate diagnosis typically requires a thorough clinical evaluation, including a detailed patient history, physical examination, and laboratory tests to assess mast cell mediators. Understanding the underlying cause of mast cell activation is essential for effective management and treatment, which may involve addressing the primary condition, using antihistamines, or other immunomodulatory therapies.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Requires understanding of underlying conditions that trigger mast cell activation.
  • Differentiation from primary mast cell disorders can be challenging.
  • Documentation must clearly establish the secondary nature of the condition.
  • Potential overlap with other hematologic conditions complicates coding.

Audit Risk Factors

  • Insufficient documentation of the underlying condition leading to mast cell activation.
  • Failure to differentiate between primary and secondary mast cell activation.
  • Inadequate clinical rationale for the diagnosis.
  • Lack of supporting laboratory results or clinical findings.

Specialty Focus

Medical Specialties

Hematology

Documentation Requirements

Detailed patient history, laboratory results indicating mast cell mediator levels, and documentation of any underlying hematologic disorders.

Common Clinical Scenarios

Patients with chronic myeloid leukemia presenting with symptoms of mast cell activation.

Billing Considerations

Ensure that the relationship between the hematologic condition and mast cell activation is clearly documented.

Allergy and Immunology

Documentation Requirements

Comprehensive allergy history, symptom diary, and results from skin tests or serum tryptase levels.

Common Clinical Scenarios

Patients experiencing allergic reactions with a known underlying autoimmune disorder.

Billing Considerations

Documenting the specific triggers and responses to treatment is crucial for accurate coding.

Coding Guidelines

Inclusion Criteria

Use D89.43 When
  • Follow official ICD
  • 10 coding guidelines, ensuring that the diagnosis is supported by clinical documentation
  • Include any relevant laboratory findings and specify the underlying condition when applicable

Exclusion Criteria

Do NOT use D89.43 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

85025CPT Code

Complete blood count (CBC) with differential

Clinical Scenario

Used to assess overall health and detect a variety of disorders, including mast cell activation.

Documentation Requirements

Document the reason for the CBC and any relevant findings.

Specialty Considerations

Hematology specialists should ensure that the CBC results are interpreted in the context of mast cell activation.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of conditions like secondary mast cell activation, improving the accuracy of diagnoses and treatment tracking.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of conditions like secondary mast cell activation, improving the accuracy of diagnoses and treatment tracking.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of conditions like secondary mast cell activation, improving the accuracy of diagnoses and treatment tracking.

Resources

Clinical References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Coding & Billing References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Frequently Asked Questions

What are the common symptoms of secondary mast cell activation?

Common symptoms include flushing, itching, abdominal pain, and in severe cases, anaphylaxis. Symptoms can vary based on the underlying condition.