ICD-10 Logo
ICDxICD-10 Medical Coding
ICD-10 Logo
ICDxICD-10 Medical Coding
ICD 10 CodesDiagnoses
ICD 10 CodesDiagnoses
ICD-10 Logo
ICDxICD-10 Medical Coding

Comprehensive ICD-10-CM code reference with AI-powered search capabilities.

© 2025 ICD Code Compass. All rights reserved.

Browse

  • All Chapters
  • All Categories
  • Diagnoses

Tools

  • AI Code Search
ICD-10-CM codes are maintained by the CDC and CMS. This tool is for reference purposes only.
v1.0.0
ICD-10 Guide
ICD-10 CodesD84.1

D84.1

Billable

Defects in the complement system

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

Code Description

ICD-10 D84.1 is a billable code used to indicate a diagnosis of defects in the complement system.

Key Diagnostic Point:

Defects in the complement system refer to a group of inherited or acquired disorders that affect the complement cascade, a crucial part of the immune system. The complement system consists of proteins that enhance the ability of antibodies and phagocytic cells to clear pathogens from an organism. Deficiencies or dysfunctions in these proteins can lead to increased susceptibility to infections, autoimmune diseases, and inflammatory conditions. Patients may present with recurrent infections, particularly with encapsulated organisms, and may also exhibit symptoms of autoimmune disorders due to the inability to regulate immune responses effectively. Diagnosis typically involves laboratory tests to assess complement levels and function, and management may include prophylactic antibiotics, immunoglobulin therapy, and treatment of associated autoimmune conditions. Understanding the nuances of these defects is essential for accurate coding and management of affected patients.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variety of underlying causes (genetic vs. acquired)
  • Overlap with autoimmune disorders
  • Need for specific laboratory test results for accurate diagnosis
  • Potential for multiple comorbid conditions

Audit Risk Factors

  • Inadequate documentation of laboratory results
  • Misclassification of autoimmune conditions
  • Failure to document recurrent infections
  • Lack of clarity on the type of complement deficiency

Specialty Focus

Medical Specialties

Immunology

Documentation Requirements

Detailed immunological assessments and laboratory results showing complement levels and function.

Common Clinical Scenarios

Patients presenting with recurrent infections or autoimmune symptoms requiring immunological evaluation.

Billing Considerations

Ensure comprehensive documentation of all clinical findings and laboratory results to support the diagnosis.

Hematology

Documentation Requirements

Complete blood counts and specific tests for complement system evaluation.

Common Clinical Scenarios

Patients with unexplained hematologic abnormalities or recurrent infections.

Billing Considerations

Document any associated hematologic conditions that may complicate the diagnosis.

Coding Guidelines

Inclusion Criteria

Use D84.1 When
  • Follow official coding guidelines for the use of D84
  • 1, ensuring that all documentation supports the diagnosis
  • Include relevant laboratory findings and clinical history

Exclusion Criteria

Do NOT use D84.1 When
  • Exclude conditions that do not meet the criteria for complement system defects

Related ICD-10 Codes

Related CPT Codes

85025CPT Code

Complete blood count (CBC) with differential

Clinical Scenario

Used to evaluate overall health and detect a variety of disorders, including hematologic conditions.

Documentation Requirements

Document the reason for the CBC and any relevant clinical findings.

Specialty Considerations

Immunologists and hematologists should ensure that the CBC is interpreted in the context of complement deficiencies.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of complement system defects, improving the ability to capture the complexity of these conditions and their management.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of complement system defects, improving the ability to capture the complexity of these conditions and their management.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of complement system defects, improving the ability to capture the complexity of these conditions and their management.

Resources

Clinical References

  • •
    Complement Deficiencies: A Guide for Clinicians

Coding & Billing References

  • •
    Complement Deficiencies: A Guide for Clinicians

Frequently Asked Questions

What are the common symptoms of defects in the complement system?

Common symptoms include recurrent infections, particularly with encapsulated bacteria, and signs of autoimmune disorders such as joint pain, skin rashes, and fatigue.