ICD-10-CM › S00-T88 › T36-T50 › T36.AX Poisoning by, adverse effect of... › T36.AX4

T36.AX4

Poisoning by fluoroquinolone antibiotics, undetermined

Not billableICD-10-CM diagnosis code.

This code exists but cannot be submitted on its own. It groups the more specific codes beneath it.

A category header for its whole life, FY2026 onwards. It has never been valid for submission on its own.

Submit one of these 3 more specific codes instead:

  • T36.AX4A Poisoning by fluoroquinolone antibiotics, undetermined, initial encounter
  • T36.AX4D Poisoning by fluoroquinolone antibiotics, undetermined, subsequent encounter
  • T36.AX4S Poisoning by fluoroquinolone antibiotics, undetermined, sequela

This code requires a seventh character. See the rule below.

What has happened to this code

Every change the publisher made, from 2026 to now.

  1. FY2026 Added to the code set Poisoning by fluoroquinolone antibiotics, undetermined

Official coding rules

Published by CDC for FY2027. A rule attached to a category binds every code beneath it, so the rules inherited from this code's ancestors are shown with the code they come from.

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

Seventh character required

  • The appropriate 7th character is to be added to each code from category T36

Excludes1 - never coded here

  • 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)

Inherited from the T36-T50 section Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)

Excludes1 - never coded here

  • toxic reaction to local anesthesia in pregnancy (O29.3-)

Excludes2 - not included here

  • abuse and dependence of psychoactive substances (F10-F19)
  • abuse of non-dependence-producing substances (F55.-)
  • immunodeficiency due to drugs (D84.821)
  • drug reaction and poisoning affecting newborn (P00-P96)
  • pathological drug intoxication (inebriation) (F10-F19)

Use additional code

  • code(s) to specify:
  • manifestations of poisoning
  • underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
  • underdosing of medication regimen (Z91.12-, Z91.13-)

Code first

  • , for adverse effects, the nature of the adverse effect, such as:
  • adverse effect NOS (T88.7)
  • aspirin gastritis (K29.-)
  • blood disorders (D56-D76)
  • contact dermatitis (L23-L25)
  • dermatitis due to substances taken internally (L27.-)
  • nephropathy (N14.0-N14.2)

Includes

  • adverse effect of correct substance properly administered
  • poisoning by overdose of substance
  • poisoning by wrong substance given or taken in error
  • underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed

Note

  • The drug giving rise to the adverse effect should be identified by use of codes from categories T36-T50 with fifth or sixth character 5.

How CDC's index refers to this code

Wording from the official alphabetic index. Much of it appears nowhere in the code description, which is why a search for the everyday phrase so often finds nothing.

Codes in the same group

CodeDescriptionStatus
T36.AX1 Poisoning by fluoroquinolone antibiotics, accidental (unintentional) Not billable
T36.AX2 Poisoning by fluoroquinolone antibiotics, intentional self-harm Not billable
T36.AX3 Poisoning by fluoroquinolone antibiotics, assault Not billable
T36.AX5 Adverse effect of fluoroquinolone antibiotics Not billable
T36.AX6 Underdosing of fluoroquinolone antibiotics Not billable