2026 ICD-10-CM Diagnosis Code T56.891SToxic effect of other metals, accidental (unintentional), sequela
T56.891S is a billable ICD-10-CM diagnosis code for toxic effect of other metals, 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
T56.891S 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 antimony compound overdose
- Accidental lithium and/or lithium compound overdose
- Accidental lithium poisoning
- Accidental poisoning by antimony compound
- Accidental poisoning by antimony fumes
- Accidental poisoning by brass fumes
- Accidental poisoning by nickel compounds
- Acute selenium poisoning
- Adverse reaction to antimony and/or antimony compound
- Allergic reaction to platinum
- Aluminum and/or aluminum compound poisoning
- Antimony compound overdose
- Antimony compound poisoning
- Bismuth poisoning
- Chronic selenium poisoning
- Cobalt poisoning
- Gold poisoning
- Heavy metal food poisoning
- Hypercalcemia caused by a drug
- Hypercalcemia caused by lithium
- Lithium and/or lithium compound overdose
- Lithium poisoning
- Molybdenum poisoning
- Non-allergic hypersensitivity to gadolinium and/or gadolinium compound
- Selenium poisoning
- Topical selenium adverse reaction
- Toxic effect of antimony and/or antimony compound
- Toxic effect of brass fumes
- Toxic effect of nickel compound
- Toxic effect of selenium and/or selenium compound
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Toxic effect of metals (T56). 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
gamma-Aminobutyric Acid
the most common inhibitory neurotransmitter in the central nervous system.Lithium
an element in the alkali metals family. it has the atomic symbol li, atomic number 3, and atomic weight [6.938; 6.997]. salts of lithium are used in treating bipolar disorder.Lithium Carbonate
a lithium salt, classified as a mood-stabilizing agent. lithium ion alters the metabolism of biogenic monoamines in the central nervous system, and affects multiple neurotransmission systems.Lithium Chloride
a salt of lithium that has been used experimentally as an immunomodulator.Lithium Compounds
inorganic compounds that contain lithium as an integral part of the molecule.Niacin
a water-soluble vitamin of the b complex occurring in various animal and plant tissues. it is required by the body for the formation of coenzymes nad and nadp. it has pellagra-curative, vasodilating, and antilipemic properties.Tellurium
an element that is a member of the chalcogen family. it has the atomic symbol te, atomic number 52, and atomic weight 127.60. it has been used as a coloring agent and in the manufacture of electrical equipment. exposure may cause nausea, vomiting, and cns depression.Nitrogenase
an enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (cyanobacteria). ec 1.18.6.1.Vanadium
a metallic element with the atomic symbol v, atomic number 23, and atomic weight 50.94. it is used in the manufacture of vanadium steel. prolonged exposure can lead to chronic intoxication caused by absorption usually via the lungs.Vanadium Compounds
inorganic compounds that contain vanadium as an integral part of the molecule.
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 |
|---|---|---|---|---|---|---|
| Antimony (compounds) (vapor) NEC | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Antimony (compounds) (vapor) NEC::anti-infectives | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Antimony (compounds) (vapor) NEC::dimercaptosuccinate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Antimony (compounds) (vapor) NEC::hydride | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Antimony (compounds) (vapor) NEC::pesticide (vapor) | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Antimony (compounds) (vapor) NEC::potassium (sodium) tartrate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Antimony (compounds) (vapor) NEC::sodium dimercaptosuccinate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Antimony (compounds) (vapor) NEC::tartrated | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Brass (fumes) | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Cobalt (nonmedicinal) (fumes) (industrial) | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Cobalt (nonmedicinal) (fumes) (industrial)::medicinal (trace) (chloride) | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Golden sulfide of antimony | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Lithium | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Lithium::gluconate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Lithium::salts (carbonate) | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::carbonate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::citrate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::hydroxide | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::oxide | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::peroxide | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::salicylate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::silicofluoride | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::sulfate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::thiosulfate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Magnesium NEC::trisilicate | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Nickel (carbonyl) (tetra-carbonyl) (fumes) (vapor) | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Nickelocene | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Selenium NEC | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Selenium NEC::disulfide or sulfide | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Selenium NEC::fumes | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Selenium NEC::sulfide | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Stibine | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Tellurium | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Tellurium::fumes | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Titanium (compounds) (vapor) | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Titanium (compounds) (vapor)::dioxide | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Titanium (compounds) (vapor)::ointment | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Titanium (compounds) (vapor)::oxide | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Titanium (compounds) (vapor)::tetrachloride | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Titanocene | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
| Vanadium | T56.891 | T56.892 | T56.893 | T56.894 | – | – |
Convert T56.891S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T56.891SOverview
Is T56.891S (Toxic effect of other metals, accidental (unintentional)) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of other metals, accidental (unintentional), sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T56.891S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the toxic effect of other metals, accidental (unintentional) itself has resolved, not the original event.
What MS-DRG does T56.891S group to?
When toxic effect of other metals, 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 T56.891S 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 other metals, accidental (unintentional), sequela on inpatient claims.
What is the ICD-9 equivalent of T56.891S?
Under the General Equivalence Mappings, toxic effect of other metals, 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.
