2027 ICD-10-CM Diagnosis Code T54.3X3AToxic effect of corrosive alkalis and alkali-like substances, assault, initial encounter
T54.3X3A is a billable ICD-10-CM diagnosis code for toxic effect of corrosive alkalis and alkali-like substances, assault, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 917 through 918. Coders also document this condition as assault by caustic alkalies. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under External cause codes: fire/burn; initial encounter; External cause codes: intent of injury, assault; and Toxic effects, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Assault by caustic alkalies
- Assault by corrosive substance, except poisoning
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 2027, published by CMS and the National Center for Health Statistics.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to T54.3X3A: its own notes plus those printed at T54, block T51-T65, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- contact with and (suspected) exposure to toxic substances (Z77.-)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Notes
General instructions on how these codes are used.
- When no intent is indicated code to accidental. Undetermined intent is only for use when there is specific documentation in the record that the intent of the toxic effect cannot be determined.
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- The appropriate 7th character is to be added to each code from category T54
- Ainitial encounter this code
- Dsubsequent encounter
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Alkalies
usually a hydroxide of lithium, sodium, potassium, rubidium or cesium, but also the carbonates of these metals, ammonia, and the amines. (grant & hackh's chemical dictionary, 5th ed)Lye
generally speaking, it is the alkaline substance obtained from wood ashes by percolation. preparations of lye can be solutions of either potassium or sodium hydroxide. the term lye, is also used to refer to the household product which is a mixture of sodium hydroxide and sodium carbonate.
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 | – | – |
| Ammonia (fumes) (gas) (vapor)::liquid (household) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Ammonium::carbonate | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Ammonium::compounds (household) NEC | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Ammonium::compounds (household) NEC::industrial | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Calcium::hydrate, hydroxide | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Calcium::hypochlorite | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Calcium::oxide | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Caustic (s) NEC::alkali | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Caustic (s) NEC::hydroxide | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Caustic (s) NEC::potash | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Caustic (s) NEC::soda | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Chloride of lime (bleach) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Chlorinated::lime (bleach) | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Chlorine (fumes) (gas)::bleach | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Disinfectant::alkaline | 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 | – | – |
| Potassium (salts) NEC::carbonate | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Potassium (salts) NEC::hydroxide | 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 | – | – |
| Sodium::carbonate NEC | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Sodium::hydroxide | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Sodium::hypochlorite (bleach) NEC | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Sodium::hypochlorite (bleach) NEC::disinfectant | T54.3X1 | T54.3X2 | T54.3X3 | T54.3X4 | – | – |
| Sodium::hypochlorite (bleach) NEC::vapor | 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 | – | – |
Convert T54.3X3A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T54.3X3AOverview
Is T54.3X3A 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, assault, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in T54.3X3A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for toxic effect of corrosive alkalis and alkali-like substances, assault, such as an emergency visit or first evaluation.
What MS-DRG does T54.3X3A group to?
When toxic effect of corrosive alkalis and alkali-like substances, assault, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 918, 917, with relative weights from 0.8716 to 1.5698 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T54.3X3A be reported with a code from Z77?
Not as a rule. The Excludes1 note at block T51-T65, which applies to T54.3X3A, lists "contact with and (suspected) exposure to toxic substances (Z77.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of T54.3X3A?
Under the General Equivalence Mappings, toxic effect of corrosive alkalis and alkali-like substances, assault, initial encounter converts to ICD-9-CM 983.2 (toxic eff caustic alkali) and E961 (assault-corrosiv/caust). The mapping is approximate, so confirm the match fits the documentation.
