Muscle Weakness ICD-10 Code: M62.81
Last updated: August 28, 2026
The ICD-10 code for generalized muscle weakness is M62.81. Use it when true muscle weakness is documented on exam. For generalized weakness, fatigue, or asthenia without documented muscle weakness, use R53.1 instead - the distinction matters for audits and risk adjustment.
Primary Code Details
| Code | Description | Billable |
|---|---|---|
| M62.81 | Muscle weakness (generalized) | Yes |
Related Codes
Documentation Requirements
- Document objective muscle weakness on examination (e.g., strength graded 4/5), not just subjective fatigue
- Specify generalized vs focal weakness - focal deficits point to neurological codes instead
- Note contributing factors: deconditioning, prolonged hospitalization, steroid use, neuropathy
- For sarcopenia (M62.84), documentation should reference muscle mass loss, not just weakness
Common Coding Scenarios
Documentation:
"Following 10-day admission, exam shows generalized 4/5 strength in proximal muscle groups. PT ordered."
Code:
M62.81 - Muscle weakness (generalized)
Rationale:
Objective, examined muscle weakness supports M62.81 and the medical necessity for therapy services.
Documentation:
"Patient endorses feeling weak and tired for a month. Strength 5/5 throughout on exam."
Code:
R53.1 - Weakness
Rationale:
Without objective muscle weakness, the symptom is asthenia - R53.1. Using M62.81 here is a common audit finding.
Documentation:
"DEXA-confirmed low muscle mass with low grip strength in a 78-year-old; documented as sarcopenia."
Code:
M62.84 - Sarcopenia
Rationale:
Documented sarcopenia has its own specific code. Add M62.81 only if separate generalized weakness is also documented.
Frequently Asked Questions
M62.81 (Muscle weakness, generalized) when weakness of muscles is documented on examination. It is a billable code frequently used to support physical therapy medical necessity.
M62.81 is objective muscle weakness found on exam; R53.1 is generalized weakness or asthenia - the subjective feeling of being weak. Auditors look for exam findings when M62.81 is billed.
There is no dedicated deconditioning code. Coders typically use M62.81 when muscle weakness is examined and documented, or R53.1 for generalized weakness; some payers accept Z72.3 or R53.81 depending on documentation.
Related Resources
Last updated: August 2026. Code data reflects ICD-10-CM 2026 version. This guide is for educational purposes only. Always verify codes against current official guidelines.