2026 ICD-10-CM Diagnosis Code T36.4X5SAdverse effect of tetracyclines, sequela
T36.4X5S is a billable ICD-10-CM diagnosis code for adverse effect of tetracyclines, 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 not accepted as a principal diagnosis by the Medicare Code Editor and 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
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T36.4X5S.
Present on Admission (POA)Billing
T36.4X5S 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.
- Adverse reaction to clomocycline
- Chemical esophagitis
- Chlortetracycline adverse reaction
- Color changes during tooth formation
- Demeclocycline adverse reaction
- Doxycycline adverse reaction
- Esophagitis medicamentosa
- Intrinsic staining of tooth - drug-induced
- Intrinsic staining of tooth caused by tetracycline
- Lymecycline adverse reaction
- Minocycline adverse reaction
- Oxytetracycline adverse reaction
- Pill esophagitis
- Pill esophagitis caused by tetracycline
- Posteruptive color change of tooth
- Posteruptive tooth staining caused by drug
- Posteruptive tooth staining caused by tetracycline
- Pre-eruptive color change of tooth
- Tetracycline adverse reaction
- Tetracyclines group adverse reaction
Coding GuidelinesGuidance
When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug.
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
Drug Reactions
Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions, such as drug interactions, side effects, and allergies.
The full article covers:
- What is a drug interaction?
- What are side effects?
- What are drug allergies?
- How can I stay safe when taking medicines?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T36.4X5S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T36.4X5SOverview
Is T36.4X5S (Adverse effect of tetracyclines) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of tetracyclines, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T36.4X5S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the adverse effect of tetracyclines itself has resolved, not the original event.
What MS-DRG does T36.4X5S group to?
On inpatient claims, adverse effect of tetracyclines, sequela maps to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T36.4X5S be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of tetracyclines, sequela describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
Is T36.4X5S 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 adverse effect of tetracyclines, sequela on inpatient claims.
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.
