2026 ICD-10-CM Diagnosis Code T36Poisoning by, adverse effect of and underdosing of systemic antibiotics
T36 is a non-billable ICD-10-CM category code for poisoning by, adverse effect of and underdosing of systemic antibiotics, so it cannot be submitted on claims. Use a more specific code from this category instead, such as T36.0X1A, T36.0X1D, T36.0X1S, and T36.0X2A.
Code Identity
Code Classification
Specific Coding for Systemic antibioticsOverview
Non-specific codes like T36 require more characters. Use one of these billable codes instead:
T36.0 for Poisoning by, adverse effect of and underdosing of penicillins
T36.0X for Poisoning by, adverse effect of and underdosing of penicillins
T36.1 for Poisoning by, adverse effect of and underdosing of cephalosporins and other beta-lactam antibiotics
T36.1X for Poisoning by, adverse effect of and underdosing of cephalosporins and other beta-lactam antibiotics
T36.2 for Poisoning by, adverse effect of and underdosing of chloramphenicol group
T36.2X for Poisoning by, adverse effect of and underdosing of chloramphenicol group
T36.3 for Poisoning by, adverse effect of and underdosing of macrolides
T36.3X for Poisoning by, adverse effect of and underdosing of macrolides
T36.4 for Poisoning by, adverse effect of and underdosing of tetracyclines
T36.4X for Poisoning by, adverse effect of and underdosing of tetracyclines
T36.5 for Poisoning by, adverse effect of and underdosing of aminoglycosides
T36.5X for Poisoning by, adverse effect of and underdosing of aminoglycosides
T36.6 for Poisoning by, adverse effect of and underdosing of rifampicins
T36.6X for Poisoning by, adverse effect of and underdosing of rifampicins
T36.7 for Poisoning by, adverse effect of and underdosing of antifungal antibiotics, systemically used
T36.7X for Poisoning by, adverse effect of and underdosing of antifungal antibiotics, systemically used
T36.8 for Poisoning by, adverse effect of and underdosing of other systemic antibiotics
T36.8X for Poisoning by, adverse effect of and underdosing of other systemic antibiotics
T36.9 for Poisoning by, adverse effect of and underdosing of unspecified systemic antibiotic
T36.91 for Poisoning by unspecified systemic antibiotic, accidental (unintentional)
T36.92 for Poisoning by unspecified systemic antibiotic, intentional self-harm
T36.93 for Poisoning by unspecified systemic antibiotic, assault
T36.94 for Poisoning by unspecified systemic antibiotic, undetermined
T36.95 for Adverse effect of unspecified systemic antibiotic
T36.96 for Underdosing of unspecified systemic antibiotic
T36.A for Poisoning by, adverse effect of and underdosing of fluoroquinolone antibiotics
T36.AX for Poisoning by, adverse effect of and underdosing of fluoroquinolone antibiotics
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.
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 1 Excludes
- antineoplastic antibiotics T45.1
- locally applied antibiotic NEC T49.0
- topically used antibiotic for ear, nose and throat T49.6
- topically used antibiotic for eye T49.5
7th Character Note
- The appropriate 7th character is to be added to each code from category T36
7th Character
- A - initial encounter
- D - subsequent encounter
- S - sequela
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
Indicates that a seventh character is to be assigned to codes in a subcategory.
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.
Code HistoryHistory
Questions About T36Overview
Is T36 a billable code?
No. This is a category header that groups the codes for poisoning by, adverse effect of and underdosing of systemic antibiotics, and headers cannot be submitted on claims. Claims for poisoning by, adverse effect of and underdosing of systemic antibiotics need a more specific code from this category, such as T36.0X1A, T36.0X1D, and T36.0X1S.
