ICD-10 T30.4
Billable / SpecificCorrosion of unspecified body region, unspecified degree
About ICD-10-CM T30.4
ICD-10-CM code T30.4 represents Corrosion of unspecified body region, unspecified degree. This is a billable/specific code in the Injury, Poisoning, and External Causes chapter (block T30). The 2026 edition of ICD-10-CM T30.4 became effective on October 1, 2025.
Coding Tips for T30.4
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
Injury codes require a 7th character: A (initial encounter, active treatment), D (subsequent, healing/recovery), S (sequela, late effect of original injury). Codes with fewer than 6 characters need the placeholder X to bring them to 6 characters before adding the 7th. Wrong or missing 7th character is the #1 cause of injury claim denials.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under T30.4. Per CMS ICD-10-CM Tabular 2026.
- This code is not for inpatient use. Code to specified site and degree of corrosion
- Corrosion NOS
- Multiple corrosion NOS
Medicare LCD Coverage for T30.4
Local Coverage Determinations (LCDs) from CMS MACs that list T30.4 as a covered diagnosis.
Showing top 10 of 59 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing T30.4.
1 Cigna
5 Medicare
CPT Codes Commonly Billed with T30.4
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Convert T30.4 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| T30.4 | 9490 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To T30.4
Other codes in section T30-T32 (Burns and corrosions of multiple and unspecified body regions).
ICD-10 T30.4, Billing FAQ
Is ICD-10 code T30.4 billable? +
Yes, T30.4 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to T30.4? +
ICD-10 T30.4 includes: This code is not for inpatient use. Code to specified site and degree of corrosion; Corrosion NOS; Multiple corrosion NOS.
What ICD-9 codes does T30.4 map to? +
Per CMS GEMs, T30.4 maps to ICD-9 codes: 9490. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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