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v1.0.0
ICD-10 Guide
DiagnosesAltered Level Of Consciousness

Altered Level Of Consciousness

ICD-10 Coding for Altered Level of Consciousness(R40.0, R40.1, R40.2)

PRIMARY SPECIALTYEmergency Medicine
COMPLEXITYHigh
LAST UPDATED09/15/2025
Sam Tuffun, PT, DPT
Physical Therapist | Medical Coding & Billing Contributor

Diagnosis Overview

What is Altered Level Of Consciousness?
Essential facts and insights about Altered Level of Consciousness

Key Clinical Considerations:

  • Altered level of consciousness can present as confusion, lethargy, stupor, or coma.
  • Laboratory findings may include abnormal glucose levels, electrolyte imbalances, or toxicology screens.
  • Physical examination may reveal changes in responsiveness, orientation, or neurological deficits.
  • Imaging studies such as CT or MRI may be necessary to rule out structural causes like hemorrhage or tumors.
  • Severity can be assessed using scales such as the Glasgow Coma Scale (GCS), which ranges from 3 to 15.

Clinical Information

Clinical Criteria & Documentation Requirements

  • Document the patient's level of consciousness using standardized scales (e.g., GCS).
  • Include specific terms such as 'confusion', 'stupor', or 'coma' in the medical record.
  • Examples include: 'Patient presents with altered level of consciousness, GCS 12, and is disoriented to time and place.'
  • Medical necessity must be established through documentation of symptoms and clinical findings.
  • Quality measures may require documentation of interventions and outcomes related to consciousness levels.

Coding Guidelines

Usage Guidelines & Examples

  • Use R40.0 for coma, R40.1 for stupor, and R40.2 for other altered states of consciousness.
  • Do not use these codes for conditions like syncope or seizures, which have distinct codes.
  • R40.0, R40.1, and R40.2 are related but specify different levels of consciousness impairment.
  • Common errors include using the wrong code for the level of consciousness or failing to document severity.
  • In complex cases, consider additional codes for underlying conditions contributing to altered consciousness.

Code Exclusions

Important Exclusions

  • Excludes conditions like syncope (R55) and seizures (G40) which have separate coding.
  • Alternative codes for excluded conditions should be used to accurately reflect the patient's diagnosis.
  • Conditions are excluded due to differing pathophysiology and treatment approaches.
  • Common mistakes include misclassifying syncope as altered consciousness.
  • Related but distinct conditions include delirium and dementia, which require different diagnostic criteria.

Related ICD-10 Codes

Primary Codes
R40.0
Coma, unspecified
R40.1
Stupor
R40.2
Other altered mental status
Differential Codes
R41.82
R41.82
when cognitive impairment is present without changes in arousal.
R40.2
R40.2
when the patient is completely unresponsive.
R40.1
R40.1
when the patient responds to vigorous stimuli.

Related CPT Codes

CPT codes will be available in a future update.

Specialty Focus

Primary Specialty

Emergency Medicine

Specialty Applications

  • Applies to conditions such as traumatic brain injury, stroke, or metabolic disturbances.
  • Patient populations include all ages, with particular attention to the elderly and those with chronic illnesses.
  • Clinical settings include emergency departments, inpatient units, and outpatient follow-ups.
  • Specialty-specific applications are relevant in emergency medicine, neurology, and critical care.
  • Treatment contexts include acute management of altered consciousness and ongoing monitoring.

Coding Complexity

High Complexity

This diagnosis requires careful attention to:

  • Comprehensive clinical documentation
  • Accurate code selection based on clinical criteria
  • Proper exclusion considerations
  • Specialty-specific coding guidelines

Documentation

Documentation Templates

Template 1

Template: 'Patient diagnosed with altered level of consciousness based on clinical findings of confusion and disorientation.'

Template 2

Template: 'Clinical presentation consistent with altered consciousness including lethargy and impaired responsiveness.'

Template 3

Template: 'Diagnostic criteria for altered consciousness met as evidenced by GCS score of 10.'

Template 4

Template: 'Treatment plan initiated for altered consciousness with intravenous fluids and monitoring.'

Template 5

Template: 'Follow-up care for altered consciousness including neurological assessments and vital sign monitoring.'

Billing Information

Billing Considerations

  • Ensure proper documentation for billing
  • Verify code specificity requirements
  • Check for any additional codes needed
  • Review payer-specific guidelines

Common Issues

  • Insufficient clinical documentation
  • Incorrect code selection
  • Missing supporting diagnoses
  • Timing and frequency documentation

Frequently Asked Questions

What documentation is required for this diagnosis?

Document the patient's level of consciousness, clinical findings, and any diagnostic tests performed.

How does this differ from similar diagnoses?

Altered level of consciousness is characterized by a change in awareness, while conditions like delirium involve fluctuating attention.

What are common billing considerations?

Ensure that the diagnosis is supported by clinical findings and that medical necessity is clearly documented.

What procedures are typically associated?

CPT codes for neurological assessments, imaging studies, and laboratory tests may be relevant.

Are there any quality reporting implications?

Quality measures may include tracking outcomes related to interventions for altered consciousness.