2026 ICD-10-CM Diagnosis Code T54.3X1SToxic effect of corrosive alkalis and alkali-like substances, accidental (unintentional), sequela
T54.3X1S is a billable ICD-10-CM diagnosis code for toxic effect of corrosive alkalis and alkali-like substances, 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
T54.3X1S 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 lye
- Accidental poisoning by caustic alkalis
- Accidental poisoning by lye
- Accidental poisoning by sodium hydroxide
- Alkali burn of skin
- Alkaline chemical burn of conjunctival sac
- Alkaline chemical burn of cornea
- Alkaline chemical burn of cornea and conjunctival sac
- Alkaline chemical burn of cornea AND/OR conjunctival sac
- Burn of conjunctival sac
- Burn of cornea and conjunctival sac
- Burn of esophagus
- Burning caused by ammonia
- Burning caused by caustic alkali
- Burning caused by caustic oven cleaner
- Burning caused by cement
- Burning caused by lime
- Chemical burn injury to conjunctiva
- Chemical burn of esophagus
- Chemical burn of face
- Chemical burn of gastrointestinal tract
- Chemical burn of internal organ
- Chemical injury to cornea
- Corrosion of esophagus
- Esophageal injury caused by alkali
- Lye causing toxic effect
- Toxic effect of caustic alkali
- Toxic effect of potassium hydroxide
- Toxic effect of sodium hydroxide
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.
Clinical InformationClinical
Burn of Esophagus
thermal or caustic injury to the esophagus.
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 |
|---|---|---|---|---|---|---|
| Alkali (caustic) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Chloride of lime (bleach) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Drano (drain cleaner) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Hydroxide, caustic | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Lime (chloride) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Lye (concentrated) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Potash (caustic) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Quicklime | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Soda (caustic) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Soda (caustic)::bicarb | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Soda (caustic)::chlorinated | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Triethanolamine NEC | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Triethanolamine NEC::detergent | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Triethanolamine NEC::trinitrate (biphosphate) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
Convert T54.3X1S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T54.3X1SOverview
Is T54.3X1S a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of corrosive alkalis and alkali-like substances, accidental (unintentional), sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T54.3X1S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the toxic effect of corrosive alkalis and alkali-like substances, accidental (unintentional) itself has resolved, not the original event.
What MS-DRG does T54.3X1S group to?
When toxic effect of corrosive alkalis and alkali-like substances, 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 T54.3X1S 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 corrosive alkalis and alkali-like substances, accidental (unintentional), sequela on inpatient claims.
What is the ICD-9 equivalent of T54.3X1S?
Under the General Equivalence Mappings, toxic effect of corrosive alkalis and alkali-like substances, 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.
