2026 ICD-10-CM Diagnosis Code T57.8X4AToxic effect of other specified inorganic substances, undetermined, initial encounter
T57.8X4A is a billable ICD-10-CM diagnosis code for toxic effect of other specified inorganic substances, undetermined, 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 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 917 through 918. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under External cause codes: intent of injury, undetermined; External cause codes: poisoning by non-drug; and Toxic effects, initial encounter.
Code Identity
Code Classification
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Toxic effect of other inorganic substances (T57). 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
Asbestos
asbestos. fibrous incombustible mineral composed of magnesium and calcium silicates with or without other elements. it is relatively inert chemically and used in thermal insulation and fireproofing. inhalation of dust causes asbestosis and later lung and gastrointestinal neoplasms.Asbestos, Amosite
asbestos, grunerite. a monoclinic amphibole form of asbestos having long fibers and a high iron content. it is used in insulation. (mcgraw-hill dictionary of scientific and technical terms, 4th ed)Asbestos, Amphibole
a class of asbestos that includes silicates of magnesium, iron, calcium, and sodium. the fibers are generally brittle and cannot be spun, but are more resistant to chemicals and heat than asbestos, serpentine. (from hawley's condensed chemical dictionary, 11th ed)Asbestos, Crocidolite
a lavender, acid-resistant asbestos.Asbestos, Serpentine
a type of asbestos that occurs in nature as the dihydrate of magnesium silicate. it exists in two forms: antigorite, a plated variety, and chrysotile, a fibrous variety. the latter makes up 95% of all asbestos products. (from merck index, 11th ed, p.893)Asbestosis
a form of pneumoconiosis caused by inhalation of asbestos fibers which elicit potent inflammatory responses in the parenchyma of the lung. the disease is characterized by interstitial fibrosis of the lung, varying from scattered sites to extensive scarring of the alveolar interstitium.
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 |
|---|---|---|---|---|---|---|
| Asbestos | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Barium (carbonate) (chloride) (sulfite) | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Barium (carbonate) (chloride) (sulfite)::diagnostic agent | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Barium (carbonate) (chloride) (sulfite)::pesticide | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Barium (carbonate) (chloride) (sulfite)::rodenticide | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Barium (carbonate) (chloride) (sulfite)::sulfate (medicinal) | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Bichromates (calcium) (potassium) (sodium) (crystals) | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Bichromates (calcium) (potassium) (sodium) (crystals)::fumes | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Borane complex | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Borate (s) | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Borate (s)::buffer | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Borate (s)::cleanser | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Borate (s)::sodium | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Boron | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Boron::hydride NEC | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Boron::hydride NEC::fumes or gas | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Boron::trifluoride | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Chloramine | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Chloramine::T | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Chloramine::topical | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Decaborane | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
| Decaborane::fumes | T57.8X1 | T57.8X2 | T57.8X3 | T57.8X4 | – | – |
Convert T57.8X4A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T57.8X4AOverview
Is T57.8X4A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of other specified inorganic substances, undetermined, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T57.8X4A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for toxic effect of other specified inorganic substances, undetermined, such as an emergency visit or first evaluation.
What MS-DRG does T57.8X4A group to?
When toxic effect of other specified inorganic substances, undetermined, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 917, 918, with relative weights from 0.8571 to 1.5684 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of T57.8X4A?
Under the General Equivalence Mappings, toxic effect of other specified inorganic substances, undetermined, initial encounter converts to ICD-9-CM 989.89 (tox eff nonmed subst NEC), 989.89 (tox eff nonmed subst NEC), and E980.9 (undeter pois-sol/liq NEC). 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.
