T36 Poisoning by, adverse effect of and underdosing of systemic antibiotics

⚠ Non-Billable ICD-10-CM 2026
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The ICD-10-CM code for Poisoning by, adverse effect of and underdosing of systemic antibiotics is T36 (FY2026). It is a non-billable category code — select a more specific code below for claims.

Classification

Section
T36-T50: Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)
Category T36
88 codes (66 billable)
FY2026 Status
Stable since FY2024
Excludes1
Not coded here. These conditions should NOT be coded together with T36.
  • 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)

Official Coding Guidelines

T36-T65 are combination codes; no additional external cause code

e. Adverse Effects, Poisoning, Underdosing and Toxic Effects Codes in categories T36-T65 are combination codes that include the substance that was taken as well as the intent. No additional external cause code is required for poisonings, toxic effects, adverse effects and underdosing codes.

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.19.e
Adverse effect: code effect then T36–T50 with 5th/6th char 5

(a) Adverse Effect 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 (T36-T50). The code for the drug should have a 5th or 6th character “5” (for example T36.0X5-) Examples of the nature of an adverse effect are tachycardia, delirium, gastrointestinal hemorrhaging, vomiting, hypokalemia, hepatitis, renal failure, or respiratory failure.

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.19.e.5.a

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

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Reference T36 with the canonical source and edition:

T36 — Poisoning by, adverse effect of and underdosing of systemic antibiotics. ICD-10 Coding Pro (ICD-10-CM FY2026). https://icd10codingpro.com/codes/T36

Canonical URL: https://icd10codingpro.com/codes/T36

Related Codes

All Codes in T36

Every most-specific code under T36 Poisoning by, adverse effect of and underdosing of systemic antibiotics (66 codes):

Show the complete T36 code list
T36.0X1 Poisoning by penicillins, accidental (unintentional) T36.0X2 Poisoning by penicillins, intentional self-harm T36.0X3 Poisoning by penicillins, assault T36.0X4 Poisoning by penicillins, undetermined T36.0X5 Adverse effect of penicillins T36.0X6 Underdosing of penicillins T36.1X1 Poisoning by cephalosporins and other beta-lactam antibiotics, accidental (unintentional) T36.1X2 Poisoning by cephalosporins and other beta-lactam antibiotics, intentional self-harm T36.1X3 Poisoning by cephalosporins and other beta-lactam antibiotics, assault T36.1X4 Poisoning by cephalosporins and other beta-lactam antibiotics, undetermined T36.1X5 Adverse effect of cephalosporins and other beta-lactam antibiotics T36.1X6 Underdosing of cephalosporins and other beta-lactam antibiotics T36.2X1 Poisoning by chloramphenicol group, accidental (unintentional) T36.2X2 Poisoning by chloramphenicol group, intentional self-harm T36.2X3 Poisoning by chloramphenicol group, assault T36.2X4 Poisoning by chloramphenicol group, undetermined T36.2X5 Adverse effect of chloramphenicol group T36.2X6 Underdosing of chloramphenicol group T36.3X1 Poisoning by macrolides, accidental (unintentional) T36.3X2 Poisoning by macrolides, intentional self-harm T36.3X3 Poisoning by macrolides, assault T36.3X4 Poisoning by macrolides, undetermined T36.3X5 Adverse effect of macrolides T36.3X6 Underdosing of macrolides T36.4X1 Poisoning by tetracyclines, accidental (unintentional) T36.4X2 Poisoning by tetracyclines, intentional self-harm T36.4X3 Poisoning by tetracyclines, assault T36.4X4 Poisoning by tetracyclines, undetermined T36.4X5 Adverse effect of tetracyclines T36.4X6 Underdosing of tetracyclines T36.5X1 Poisoning by aminoglycosides, accidental (unintentional) T36.5X2 Poisoning by aminoglycosides, intentional self-harm T36.5X3 Poisoning by aminoglycosides, assault T36.5X4 Poisoning by aminoglycosides, undetermined T36.5X5 Adverse effect of aminoglycosides T36.5X6 Underdosing of aminoglycosides T36.6X1 Poisoning by rifampicins, accidental (unintentional) T36.6X2 Poisoning by rifampicins, intentional self-harm T36.6X3 Poisoning by rifampicins, assault T36.6X4 Poisoning by rifampicins, undetermined T36.6X5 Adverse effect of rifampicins T36.6X6 Underdosing of rifampicins T36.7X1 Poisoning by antifungal antibiotics, systemically used, accidental (unintentional) T36.7X2 Poisoning by antifungal antibiotics, systemically used, intentional self-harm T36.7X3 Poisoning by antifungal antibiotics, systemically used, assault T36.7X4 Poisoning by antifungal antibiotics, systemically used, undetermined T36.7X5 Adverse effect of antifungal antibiotics, systemically used T36.7X6 Underdosing of antifungal antibiotics, systemically used T36.8X1 Poisoning by other systemic antibiotics, accidental (unintentional) T36.8X2 Poisoning by other systemic antibiotics, intentional self-harm T36.8X3 Poisoning by other systemic antibiotics, assault T36.8X4 Poisoning by other systemic antibiotics, undetermined T36.8X5 Adverse effect of other systemic antibiotics T36.8X6 Underdosing of other systemic antibiotics T36.91 Poisoning by unspecified systemic antibiotic, accidental (unintentional) T36.92 Poisoning by unspecified systemic antibiotic, intentional self-harm T36.93 Poisoning by unspecified systemic antibiotic, assault T36.94 Poisoning by unspecified systemic antibiotic, undetermined T36.95 Adverse effect of unspecified systemic antibiotic T36.96 Underdosing of unspecified systemic antibiotic T36.AX1 Poisoning by fluoroquinolone antibiotics, accidental (unintentional) T36.AX2 Poisoning by fluoroquinolone antibiotics, intentional self-harm T36.AX3 Poisoning by fluoroquinolone antibiotics, assault T36.AX4 Poisoning by fluoroquinolone antibiotics, undetermined T36.AX5 Adverse effect of fluoroquinolone antibiotics T36.AX6 Underdosing of fluoroquinolone antibiotics
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Reviewed by Prajwal Shrestha, CPC, CRC
Certified Professional Coder (CPC) and Certified Risk Adjustment Coder (CRC) · AAPC Member ID 01997614 · About · Editorial policy · Content last reviewed: 2025-10-01

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