2026 ICD-10-CM Diagnosis Code T45.511SPoisoning by anticoagulants, accidental (unintentional), sequela
T45.511S is a billable ICD-10-CM diagnosis code for poisoning by anticoagulants, 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
T45.511S 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 coumarin overdose
- Accidental coumarin poisoning
- Accidental heparin overdose
- Accidental heparin poisoning
- Accidental phenindione poisoning
- Accidental poisoning by rodenticides
- Accidental poisoning by warfarin
- Accidental warfarin overdose
- Anticoagulant overdosage
- Coumafuryl poisoning
- Coumarin overdose
- Heparin overdose
- Overdose of enoxaparin
- Poisoning by coumarin
- Poisoning by heparin
- Poisoning by phenindione
- Poisoning caused by 1,3- indandione
- Poisoning caused by warfarin
- Warfarin overdosage
Coding GuidelinesGuidance
When coding a poisoning or reaction to the improper use of a medication (e.g., overdose, wrong substance given or taken in error, wrong route of administration), first assign the appropriate code from categories T36-T50. The poisoning codes have an associated intent as their 5th or 6th character (accidental, intentional self-harm, assault and undetermined). If the intent of the poisoning is unknown or unspecified, code the intent as accidental intent. The undetermined intent is only for use if the documentation in the record specifies that the intent cannot be determined. Use additional code(s) for all manifestations of poisonings.
The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of primarily systemic and hematological agents, not elsewhere classified (T45). 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
Acenocoumarol
a coumarin that is used as an anticoagulant. its actions and uses are similar to those of warfarin. (from martindale, the extra pharmacopoeia, 30th ed, p233)Phenindione
an indandione that has been used as an anticoagulant. phenindione has actions similar to warfarin, but it is now rarely employed because of its higher incidence of severe adverse effects. (from martindale, the extra pharmacopoeia, 30th ed, p234)Phenprocoumon
coumarin derivative that acts as a long acting oral anticoagulant.Warfarin
an anticoagulant that acts by inhibiting the synthesis of vitamin k-dependent coagulation factors. warfarin is indicated for the prophylaxis and/or treatment of venous thrombosis and its extension, pulmonary embolism, and atrial fibrillation with embolization. it is also used as an adjunct in the prophylaxis of systemic embolism after myocardial infarction. warfarin is also used as a rodenticide.
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.
Patient EducationClinical
Medication Errors
Medicines treat infectious diseases, prevent problems from chronic diseases, and ease pain. But medicines can also cause harmful reactions if not used correctly. Errors can happen in the hospital, at the health care provider's office, at the pharmacy, or at home. You can help prevent errors by:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T45.511S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T45.511SOverview
Is T45.511S (Poisoning by anticoagulants, accidental (unintentional)) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by anticoagulants, accidental (unintentional), sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T45.511S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by anticoagulants, accidental (unintentional) itself has resolved, not the original event.
What MS-DRG does T45.511S group to?
When poisoning by anticoagulants, 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 T45.511S 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 poisoning by anticoagulants, accidental (unintentional), sequela on inpatient claims.
What is the ICD-9 equivalent of T45.511S?
Under the General Equivalence Mappings, poisoning by anticoagulants, accidental (unintentional), sequela converts to ICD-9-CM 909.0 (late eff drug poisoning) and E929.2 (late eff acc poisoning). 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.
