2026 ICD-10-CM Diagnosis Code T36.4X3SPoisoning by tetracyclines, assault, sequela
T36.4X3S is a billable ICD-10-CM diagnosis code for poisoning by tetracyclines, assault, 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
T36.4X3S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
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 systemic antibiotics (T36). 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
Chlortetracycline
a tetracycline with a 7-chloro substitution.Demeclocycline
a tetracycline analog having a 7-chloro and a 6-methyl. because it is excreted more slowly than tetracycline, it maintains effective blood levels for longer periods of time.Doxycycline
a synthetic tetracycline derivative with similar antimicrobial activity.Lymecycline
a semisynthetic antibiotic related to tetracycline. it is more readily absorbed than tetracycline and can be used in lower doses.Methacycline
a broad-spectrum semisynthetic antibiotic related to tetracycline but excreted more slowly and maintaining effective blood levels for a more extended period.Minocycline
a tetracycline analog, having a 7-dimethylamino and lacking the 5 methyl and hydroxyl groups, which is effective against tetracycline-resistant staphylococcus infections.Oxytetracycline
a tetracycline analog isolated from the actinomycete streptomyces rimosus and used in a wide variety of clinical conditions.Rolitetracycline
a pyrrolidinylmethyl tetracycline.Tetracycline
a naphthacene antibiotic that inhibits amino acyl trna binding during protein synthesis.Tetracycline Resistance
nonsusceptibility of bacteria to the action of tetracycline which inhibits aminoacyl-trna binding to the 30s ribosomal subunit during protein synthesis.Tetracyclines
closely congeneric derivatives of the polycyclic naphthacenecarboxamide. (gilman et al., goodman and gilman's the pharmacological basis of therapeutics, 8th ed, p1117)
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
Antibiotics
Antibiotics are medicines that fight bacterial infections in people and animals. They work by killing the bacteria or by making it hard for the bacteria to grow and multiply.
The full article covers:
- What are antibiotics?
- What do antibiotics treat?
- Do antibiotics treat viral infections?
- What are the side effects of antibiotics?
- Why is it important to take antibiotics only when they're needed?
- How do I use antibiotics correctly?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T36.4X3S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T36.4X3SOverview
Is T36.4X3S (Poisoning by tetracyclines, assault) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by tetracyclines, assault, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T36.4X3S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by tetracyclines, assault itself has resolved, not the original event.
What MS-DRG does T36.4X3S group to?
When poisoning by tetracyclines, assault, 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 T36.4X3S 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 tetracyclines, assault, sequela on inpatient claims.
What is the ICD-9 equivalent of T36.4X3S?
Under the General Equivalence Mappings, poisoning by tetracyclines, assault, sequela converts to ICD-9-CM 909.0 (late eff drug poisoning) and E969 (late effect assault). 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.
