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

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

Chapter

19: Injury, poisoning and certain other consequences of external causes (S00-T88)

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

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.

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.

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

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool