2026 ICD-10-CM Diagnosis Code T36.2X4SPoisoning by chloramphenicol group, undetermined, sequela
T36.2X4S is a billable ICD-10-CM diagnosis code for poisoning by chloramphenicol group, undetermined, 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
T36.2X4S 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
Chloramphenicol
an antibiotic first isolated from cultures of streptomyces venequelae in 1947 but now produced synthetically. it has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. it acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (from martindale, the extra pharmacopoeia, 29th ed, p106)Chloramphenicol O-Acetyltransferase
an enzyme that catalyzes the acetylation of chloramphenicol to yield chloramphenicol 3-acetate. since chloramphenicol 3-acetate does not bind to bacterial ribosomes and is not an inhibitor of peptidyltransferase, the enzyme is responsible for the naturally occurring chloramphenicol resistance in bacteria. the enzyme, for which variants are known, is found in both gram-negative and gram-positive bacteria. ec 2.3.1.28.Chloramphenicol Resistance
nonsusceptibility of bacteria to the action of chloramphenicol, a potent inhibitor of protein synthesis in the 50s ribosomal subunit where amino acids are added to nascent bacterial polypeptides.Thiamphenicol
a methylsulfonyl analog of chloramphenicol. it is an antibiotic and immunosuppressive agent.
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 |
|---|---|---|---|---|---|---|
| Chloramphenicol | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Chloramphenicol::ENT agent | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Chloramphenicol::ophthalmic preparation | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Chloramphenicol::topical NEC | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Chloromycetin | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Chloromycetin::ENT agent | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Chloromycetin::ophthalmic preparation | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Chloromycetin::otic solution | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Chloromycetin::topical NEC | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Cloponone | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Cloramfenicol | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
| Thiamphenicol | T36.2X1 | T36.2X2 | T36.2X3 | T36.2X4 | T36.2X5 | T36.2X6 |
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 T36.2X4S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T36.2X4SOverview
Is T36.2X4S (Poisoning by chloramphenicol group, undetermined) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by chloramphenicol group, undetermined, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T36.2X4S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by chloramphenicol group, undetermined itself has resolved, not the original event.
What MS-DRG does T36.2X4S group to?
When poisoning by chloramphenicol group, undetermined, 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 T36.2X4S 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 chloramphenicol group, undetermined, sequela on inpatient claims.
What is the ICD-9 equivalent of T36.2X4S?
Under the General Equivalence Mappings, poisoning by chloramphenicol group, undetermined, sequela converts to ICD-9-CM 909.0 (late eff drug poisoning) and E989 (late eff inj-undet circ). 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.
