D8940 - A condition where certain immune cells (mast cells) become overactive and release chemicals that cause allergic-like symptoms

International Classification of Diseases

Last updated: 10/3/2025

What is a ICD-10 Code?

ICD-10 (International Classification of Diseases, 10th Revision) codes are used to classify and code all diagnoses, symptoms, and procedures recorded in association with hospital care. These codes provide a standardized way to track health conditions and their treatment outcomes.

Detailed Description

Mast cell activation syndrome is a condition where mast cells, which are immune system cells that normally help protect your body, become overactive and release too many chemicals like histamine. This can cause symptoms similar to allergic reactions, such as flushing, itching, hives, digestive problems, fatigue, and sometimes more serious reactions. The 'unspecified' designation means the exact type or cause of the mast cell activation hasn't been determined yet. This diagnosis often requires specialized testing and may need management by specialists who understand this complex condition.

Additional Information

This is a complex condition that often requires ongoing management and may take time to diagnose properly. Symptoms can vary widely between patients and may be triggered by various factors including stress, certain foods, medications, or environmental factors.

Category

Immune System Disorder

Medical Specialty

Allergy/Immunology, Hematology

Expected Costs

Your actual cost will depend on your insurance coverage, provider location, and specific circumstances.

What's Required Before This

  • Specialized blood tests
  • Symptom evaluation
  • Possible bone marrow biopsy
  • Tryptase level testing

What to Expect After

  • Regular monitoring with specialist
  • Medication management
  • Trigger avoidance
  • Emergency action plan
  • Possible dietary modifications

Why Understanding This Code Matters

On Your Medical Bill

This code appears on your medical bills to identify the specific service, procedure, drug, or medical diagnosis you received. Understanding what it means helps you verify you're being charged correctly and know what to expect.

For Your Health

Knowing what this code represents helps you understand your treatment plan, ask better questions during appointments, and track your healthcare journey more effectively.

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