2027 ICD-10-CM Diagnosis Code T88.7XXAUnspecified adverse effect of drug or medicament, initial encounter

ICD-10-CM Codes›S00–T88›T80-T88›T88

ICD-10-CM T88.7XXA
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T88.7XXA is a billable ICD-10-CM diagnosis code for unspecified adverse effect of drug or medicament, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 919 through 921. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of other surgical or medical care, injury, initial encounter.

Code Identity

ICD-10-CM Code
T88.7XXA
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified adverse effect of drug or medicament, initial encounter
Short Description
Unsp adverse effect of drug or medicament, init encntr
Parent Code
T88.7
Unspecified adverse effect of drug or medicament

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT80-T88Complications of surgical and medical care, not elsewhere classified
CategoryT88Other complications of surgical and medical care, not elsewhere classified
This CodeT88.7XXAUnspecified adverse effect of drug or medicament, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adverse drug interaction
  • Adverse medication interaction with alcohol
  • Adverse medication interaction with food
  • Adverse medication interaction with medication
  • Chemotherapy-induced nausea and vomiting
  • Drug interaction with alcohol
  • Drug interaction with drug
  • Drug-induced personality disorder
  • Fixed drug reaction
  • Medication interaction
  • Medication interaction potentiation
  • Medication interaction with food
  • Multiple drug hypersensitivity syndrome
  • Nausea and vomiting
  • Non-allergic drug hypersensitivity disorder
  • Phototoxicity

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Other complications of surgical and medical care, not elsewhere classified (T88). 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 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to T88.7XXA: its own notes plus those printed at T88.7, T88, block T80-T88, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From T88.7 Unspecified adverse effect of drug or medicament applies to 3 codes

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From T88 Other complications of surgical and medical care, not elsewhere classified applies to 39 codes
  • complication following infusion, transfusion and therapeutic injection (T80.-)
  • complication following procedure NEC (T81.-)
  • complications of anesthesia in labor and delivery (O74.-)
  • complications of anesthesia in pregnancy (O29.-)
  • complications of anesthesia in puerperium (O89.-)
  • complications of devices, implants and grafts (T82-T85)
  • complications of obstetric surgery and procedure (O75.4)
  • dermatitis due to drugs and medicaments (L23.3, L24.4, L25.1, L27.0-L27.1)
  • poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4)
  • specified complications classified elsewhere
From Block T80-T88 Complications of surgical and medical care, not elsewhere classified applies to 1,683 codes
  • any encounters with medical care for postprocedural conditions in which no complications are present, such as:
  • artificial opening status (Z93.-)
  • closure of external stoma (Z43.-)
  • fitting and adjustment of external prosthetic device (Z44.-)
  • burns and corrosions from local applications and irradiation (T20-T32)
  • complications of surgical procedures during pregnancy, childbirth and the puerperium (O00-O9A)
  • mechanical complication of respirator [ventilator] (J95.850)
  • poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4 or 6)
  • postprocedural fever (R50.82)
  • specified complications classified elsewhere, such as:
  • cerebrospinal fluid leak from spinal puncture (G97.0)
  • colostomy malfunction (K94.0-)
  • disorders of fluid and electrolyte imbalance (E86-E87)
  • functional disturbances following cardiac surgery (I97.0-I97.1)
  • intraoperative and postprocedural complications of specified body systems (D78.-, E36.-, E89.-, G97.3-, G97.4, H59.3-, H59.-, H95.2-, H95.3, I97.4-, I97.5, J95.6-, J95.7, K91.6-, L76.-, M96.-, N99.-)
  • ostomy complications (J95.0-, K94.-, N99.5-)
  • postgastric surgery syndromes (K91.1)
  • postlaminectomy syndrome NEC (M96.1)
  • postmastectomy lymphedema syndrome (I97.2)
  • postsurgical blind-loop syndrome (K91.2)
  • ventilator associated pneumonia (J95.851)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From T88.7 Unspecified adverse effect of drug or medicament applies to 3 codes
  • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
From Block T80-T88 Complications of surgical and medical care, not elsewhere classified applies to 1,683 codes
  • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
  • code(s) to identify the specified condition resulting from the complication
  • code to identify devices involved and details of circumstances (Y62-Y82)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From T88 Other complications of surgical and medical care, not elsewhere classified applies to 39 codes
  • The appropriate 7th character is to be added to each code from category T88
Values for category T88 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter this code
  • Dsubsequent encounter
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name T88.7XXA, its category, or a range that includes it.

Code First 1

These codes say to code first a condition named in the note, and T88.7XXA is one of the conditions named.

  • Block T36-T50 Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances
    adverse effect NOS (T88.7) names T88.7, which includes this code

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ037
Complication of other surgical or medical care, injury, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

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.

The full article covers:

  • What is a drug interaction?
  • What are side effects?
  • What are drug allergies?
  • How can I stay safe when taking medicines?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert T88.7XXA to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
999.9 Complic med care NEC/NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About T88.7XXAOverview

What is the ICD-10 code for unspecified adverse effect of drug or medicament, initial encounter?

The ICD-10-CM code for unspecified adverse effect of drug or medicament, initial encounter is T88.7XXA (sometimes written as T887XXA). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is T88.7XXA (Unspecified adverse effect of drug or medicament) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified adverse effect of drug or medicament, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in T88.7XXA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified adverse effect of drug or medicament, such as an emergency visit or first evaluation.

What MS-DRG does T88.7XXA group to?

When unspecified adverse effect of drug or medicament, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 920, 919, 921, with relative weights from 0.6719 to 1.7624 depending on complications. Higher weights mean higher Medicare reimbursement.

Can T88.7XXA be reported with T88.8?

Not as a rule. The Excludes1 note at T88.7, which applies to T88.7XXA, lists "specified adverse effects of drugs and medicaments (A00-R94 and T80-T88.6, T88.8)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).