2026 ICD-10-CM Diagnosis Code T54.91XSToxic effect of unspecified corrosive substance, accidental (unintentional), sequela
T54.91XS is a billable ICD-10-CM diagnosis code for toxic effect of unspecified corrosive substance, accidental (unintentional), sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 922 through 923. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Poisoning/toxic effect/adverse effects/underdosing, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
T54.91XS is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Accidental burning caused by caustic and corrosive substance
- Accidental poisoning by corrosive
- Alkali burn of skin
- Bleach burn of skin
- Bleach causing toxic effect
- Borate toxicity
- Borax toxicity
- Burn of forehead
- Burning caused by caustic and corrosive substance
- Chemical burn of internal organ
- Chemical burn of skin caused by corrosive substance
- Corrosion of third degree of shoulder and upper limb, except wrist and hand
- Corrosive gastritis
- Corrosive stricture of esophagus
- Epidermal burn of forehead
- Ingestion of corrosive chemical
- Occupational injury
- Occupational injury of skin caused by corrosive substance
- Poisoning caused by corrosive chemical
- Stricture of esophagus
- Superficial corrosion of forehead
- Superficial injury of skin of forehead
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Toxic effect of corrosive substances (T54). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of Drugs and ChemicalsClinical
Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.
| Substance | Accidental | Self-harm | Assault | Undetermined | Adverse Effect | Underdosing |
|---|---|---|---|---|---|---|
| Bleach | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Borax (cleanser) | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Caustic (s) NEC | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Caustic (s) NEC::alkali | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Caustic (s) NEC::hydroxide | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Caustic (s) NEC::potash | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Caustic (s) NEC::soda | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Caustic (s) NEC::specified NEC | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Clorox (bleach) | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Corrosive NEC | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Corrosive NEC::acid NEC | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Corrosive NEC::aromatics | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Corrosive NEC::aromatics::disinfectant | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Corrosive NEC::fumes NEC | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Corrosive NEC::specified NEC | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Corrosive NEC::sublimate | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Oxidizing agent NEC | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
| Purex (bleach) | T54.91 | T54.92 | T54.93 | T54.94 | – | – |
Convert T54.91XS to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T54.91XSOverview
Is T54.91XS a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of unspecified corrosive substance, accidental (unintentional), sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T54.91XS mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the toxic effect of unspecified corrosive substance, accidental (unintentional) itself has resolved, not the original event.
What MS-DRG does T54.91XS group to?
When toxic effect of unspecified corrosive substance, accidental (unintentional), sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T54.91XS exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for toxic effect of unspecified corrosive substance, accidental (unintentional), sequela on inpatient claims.
What is the ICD-9 equivalent of T54.91XS?
Under the General Equivalence Mappings, toxic effect of unspecified corrosive substance, accidental (unintentional), sequela converts to ICD-9-CM 909.1 (late eff nonmed substanc). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
