Brain Fog ICD-10 Code: R41.82

Last updated: January 31, 2025

Quick Answer

The ICD-10 code for brain fog is R41.82 (Altered mental status, unspecified). This code is used when patients present with cognitive symptoms like mental cloudiness, difficulty concentrating, or memory issues without a specific underlying diagnosis.

Primary Code Details

Code	Description	Billable
R41.82	Altered mental status, unspecified	Yes

Related Codes

Code	Description	Billable
R41.0	Disorientation, unspecified	Yes
R41.3	Other amnesia	Yes
R41.840	Attention and concentration deficit	Yes
R41.89	Other symptoms and signs involving cognitive functions	Yes
F06.7	Mild neurocognitive disorder due to known physiological condition	Yes

Documentation Requirements

Document specific cognitive symptoms (memory issues, concentration difficulties, mental cloudiness)
Note onset and duration of symptoms
Rule out or document any underlying conditions (post-COVID, chronic fatigue, medication effects)
Include any relevant lab results or imaging findings

Common Coding Scenarios

Post-COVID Brain Fog

Documentation:

"Patient reports persistent mental cloudiness and difficulty concentrating 3 months after COVID-19 infection."

Code:

R41.82 - Altered mental status, unspecified

Rationale:

Use R41.82 for cognitive symptoms. Add U09.9 (Post COVID-19 condition) as secondary code to capture the association.

Brain Fog with Chronic Fatigue

Documentation:

"Patient presents with brain fog and persistent fatigue for 6+ months."

Code:

R41.82 - Altered mental status, unspecified

Rationale:

Code R41.82 for cognitive symptoms. If chronic fatigue syndrome is diagnosed, also code R53.82.

Frequently Asked Questions

What is the ICD-10 code for brain fog?

R41.82 (Altered mental status, unspecified) is the primary code for brain fog symptoms. This billable code captures cognitive symptoms like mental cloudiness, difficulty concentrating, and memory issues.

Is R41.82 billable?

Yes, R41.82 is a valid billable ICD-10-CM code for altered mental status, unspecified. It can be used as a primary or secondary diagnosis code.

Can I use a more specific code for brain fog?

If specific symptoms are documented, consider R41.840 (Attention and concentration deficit) or R41.3 (Other amnesia) for memory-specific issues. R41.82 is appropriate when documentation describes general cognitive impairment.

Related Resources

Last updated: January 2025. Code data reflects ICD-10-CM 2026 version. This guide is for educational purposes only. Always verify codes against current official guidelines.