What chapter does ICD-10-CM code T49 belong to?

T49 belongs to Chapter 19 of the ICD-10-CM tabular list: S00–T88 (Injury, Poisoning and Certain Other Consequences of External Causes).

T49Not billable, use a more specific code below

Poisoning by, adverse effect of and underdosing of topical agents primarily affecting skin and mucous membrane and by ophthalmological, otorhinorlaryngological and dental drugs

Q: Is ICD-10-CM code T49 billable?

No, T49 (Poisoning by, adverse effect of and underdosing of topical agents primarily affecting skin and mucous membrane and by ophthalmological, otorhinorlaryngological and dental drugs) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

In Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50), chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes

180 billable codes under T49: none are a CC or MCC; 10 map to HCC 155 (Major Depression, Moderate or Severe, without Psychosis).An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Includes: conditions that are coded here

poisoning by, adverse effect of and underdosing of glucocorticoids, topically used

Also applies, from Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)

These notes sit on T36-T50 and apply to every code under it, including T49.

Includes: conditions that are coded here

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

Excludes1: not coded here, use a different code

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

Excludes2: not included here, code separately if applicable

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)

Code first: code the underlying condition first, then this code

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)

Use additional code: add a second code for this, listed after this one

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-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Section I.C.19.e Adverse Effects, Poisoning, Underdosing and Toxic Effects (page 82), covers T49
For adverse effects, code the effect first, then T36-T50 with character 5. Sequence poisonings (unknown intent coded accidental) and toxic effects (T51-T65) first; underdosing (character 6) is never first-listed.

All codes under T49

T49 can't be used on a claim. Pick a billable code below; grey headings group them.

T49 MS-DRGs

As the principal diagnosis, the billable codes under T49 group to these 9 MS-DRGs (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 949 Aftercare with CC/MCC (70 of 180 codes)
DRG 950 Aftercare without CC/MCC (70 of 180 codes)
DRG 917 Poisoning and Toxic Effects of Drugs with MCC (50 of 180 codes)
DRG 918 Poisoning and Toxic Effects of Drugs without MCC (50 of 180 codes)
DRG 922 Other Injury, Poisoning and Toxic Effect Diagnoses with MCC (50 of 180 codes)
DRG 923 Other Injury, Poisoning and Toxic Effect Diagnoses without MCC (50 of 180 codes)
DRG 791 Prematurity with Major Problems (10 of 180 codes)
DRG 793 Full Term Neonate with Major Problems (10 of 180 codes)
DRG 951 Other Factors Influencing Health Status (10 of 180 codes)

Other codes that refer to T49

Notes on these codes point to T49.

T38.0 Excludes1: glucocorticoids, topically used (T49.-)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

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.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.