ICD-10 Codes by State: Understanding National vs State Requirements
- Jan 30, 2025
Looking for state-specific ICD-10 codes? Here's the quick answer: ICD-10-CM and ICD-10-PCS codes are nationally standardized and identical in all 50 states. There are no state-specific versions of ICD-10 codes.
However, if you're searching for "ICD-10 codes by state," you likely have questions about what does vary by state in medical coding. This guide clarifies the national standard and explains what state-level differences you need to know as a medical coder or biller.
Quick Answer: ICD-10 Is a National Standard
ICD-10-CM (diagnosis codes) and ICD-10-PCS (procedure codes) are federally mandated coding systems that apply uniformly across the United States:
| What's Standardized | Details |
|---|---|
| Code set | Same 72,000+ diagnosis codes nationwide |
| Code meanings | Identical definitions in every state |
| Annual updates | All states adopt CMS updates on October 1 |
| HIPAA mandate | Federal law requires ICD-10 for electronic claims |
| Official source | CMS.gov maintains one official code set |
Bottom line: Whether you're coding in California, Texas, New York, or any other state, you use the exact same ICD-10 codes with the same meanings.
Why ICD-10 Is Nationally Standardized
The federal government mandated ICD-10 for several important reasons:
HIPAA Compliance
The Health Insurance Portability and Accountability Act (HIPAA) requires all covered entities to use standardized code sets for electronic healthcare transactions. Under 45 CFR 162.1002, ICD-10-CM is the designated code set for diagnosis coding.
Medicare & Medicaid
The Centers for Medicare & Medicaid Services (CMS) requires ICD-10-CM for all Medicare and Medicaid claims nationwide. This creates a uniform standard that all payers follow.
Interoperability
A national coding standard enables:
- Electronic health records to share data across state lines
- Insurance claims to process consistently regardless of location
- Public health surveillance across the entire country
- Healthcare research using standardized datasets
What DOES Vary by State
While the ICD-10 codes themselves are national, several aspects of medical billing and coding do vary by state:
1. State Medicaid Coverage Policies
Each state administers its own Medicaid program with unique coverage rules:
| State Variation | Example |
|---|---|
| Covered services | Some states cover dental, vision, or behavioral health more comprehensively |
| Prior authorization | Requirements for specific diagnoses differ by state |
| Reimbursement rates | Payment amounts for the same codes vary significantly |
| Managed care plans | Each state contracts with different MCOs |
Important: The ICD-10 codes used are the same—it's the coverage and payment policies that differ.
2. Timely Filing Limits
States set different deadlines for claim submission:
| Example Limits | Timeframe |
|---|---|
| Medicare (federal) | 12 months from date of service |
| State Medicaid | Varies from 60 days to 1 year |
| Commercial payers | Varies by contract and state law |
3. State-Specific Payer Requirements
Individual payers in each state may have additional requirements:
- Specific documentation for certain diagnoses
- Local coverage determinations (LCDs)
- State-mandated billing formats
- Additional modifier requirements
4. Workers' Compensation
Workers' comp programs are state-administered with varying:
- Fee schedules
- Documentation requirements
- Authorization processes
- Accepted treatment guidelines
5. No-Fault Auto Insurance
States with no-fault auto insurance (e.g., Florida, Michigan, New York) have unique:
- PIP (Personal Injury Protection) rules
- Billing requirements for auto accident claims
- Fee schedules
Common State-Related Coding Questions
"Do I need different ICD-10 codes for different states?"
No. Use the same ICD-10 codes regardless of which state you're billing in. The code for Type 2 diabetes (E11.9) is E11.9 in every state.
"Why does my state Medicaid reject codes differently?"
Rejections are based on coverage policies, not different code sets. A state might:
- Require more specific codes than another state accepts
- Have different medical necessity requirements
- Need additional documentation for certain diagnoses
- Require prior authorization for specific conditions
"How do I find state Medicaid ICD-10 requirements?"
Check your state Medicaid program's provider manual for:
- Coverage limitations
- Prior authorization requirements
- Documentation standards
- Billing instructions
These manuals define policies, not different codes.
"Are ICD-10 codes different for Medicare vs Medicaid?"
No. Medicare, Medicaid, and commercial payers all use the same ICD-10 code set. What differs is:
- Which codes are covered for which services
- Reimbursement amounts
- Documentation requirements
- Medical necessity criteria
State Medicaid Resources
Each state has a Medicaid provider portal with billing guidelines. The ICD-10 codes are standard, but coverage policies require checking your specific state:
| Region | Key States | Note |
|---|---|---|
| Northeast | NY, PA, MA, NJ | Dense populations, complex managed care |
| Southeast | FL, GA, NC, TX | Large Medicaid populations |
| Midwest | IL, OH, MI, IN | Varies widely by state |
| West | CA, WA, AZ, CO | CA has largest Medicaid program |
Tip: Search for "[Your State] Medicaid provider manual" to find official billing requirements.
Coding Rules That ARE Nationally Standardized
These coding requirements are the same in every state:
| Guideline | Applies Everywhere |
|---|---|
| Official Coding Guidelines | CMS/NCHS guidelines apply nationwide |
| Medicare Code Edits (MCE) | Same edit logic for all Medicare claims |
| Code first/Use additional code rules | Sequencing rules are universal |
| Excludes1/Excludes2 notes | Apply the same in every state |
| 7th character requirements | National requirement for injury codes |
Start Searching ICD-10 Codes
Now that you understand ICD-10 is nationally standardized, use these tools to find the codes you need:
- Search All ICD-10 Codes - Instant keyword search
- Browse ICD-10-CM by Chapter - Navigate the full hierarchy
- Browse ICD-10-PCS - Procedure codes for inpatient billing
- AI Clinical Note Analyzer - Extract codes from documentation
- Common Codes by Specialty - Quick reference lists
- Medicare Coding Rules - MCE edits and guidelines
Summary
- ICD-10 codes are identical in all 50 states - No state-specific codes exist
- What varies by state: Medicaid coverage policies, timely filing limits, payer requirements
- Source of truth: CMS.gov maintains the official ICD-10 code set
- For state-specific rules: Check your state Medicaid provider manual for coverage policies
The code E11.65 (Type 2 diabetes with hyperglycemia) means the same thing whether you're coding in Maine or Hawaii. Focus your attention on payer-specific coverage policies, not searching for state-specific code sets.
---
Data sourced from CMS.gov. ICD-10-CM 2026 codes effective October 1, 2025.