2026 ICD-10-CM Diagnosis Code T39.311APoisoning by propionic acid derivatives, accidental (unintentional), initial encounter

ICD-10-CM Codes›S00–T88›T36-T50›T39

ICD-10-CM T39.311A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T39.311A is a billable ICD-10-CM diagnosis code for poisoning by propionic acid derivatives, accidental (unintentional), 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 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 917 through 918. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under External cause codes: intent of injury, accidental/unintentional; External cause codes: poisoning by drug; and Poisoning by drugs, initial encounter.

Code Identity

ICD-10-CM Code
T39.311A
Billable Status
Yes — Valid for Submission
Code Describes
Poisoning by propionic acid derivatives, accidental (unintentional), initial encounter
Short Description
Poisoning by propionic acid derivatives, accidental, init
Parent Code
T39.311
Poisoning by propionic acid derivatives, accidental (unintentional)

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT36-T50Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances
CategoryT39Poisoning by, adverse effect of and underdosing of nonopioid analgesics, antipyretics and antirheumatics
This CodeT39.311APoisoning by propionic acid derivatives, accidental (unintentional), initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Accidental fenoprofen overdose
  • Accidental fenoprofen poisoning
  • Accidental flurbiprofen overdose
  • Accidental flurbiprofen poisoning
  • Accidental ibuprofen overdose
  • Accidental ketoprofen overdose
  • Accidental naproxen overdose
  • Accidental poisoning by ibuprofen
  • Accidental poisoning by ketoprofen
  • Accidental poisoning by naproxen
  • Accidental tiaprofenic acid overdose
  • Accidental tiaprofenic acid poisoning
  • Fenoprofen overdose
  • Fenoprofen poisoning
  • Flurbiprofen overdose
  • Flurbiprofen poisoning
  • Ibuprofen overdose
  • Ibuprofen poisoning
  • Ketoprofen overdose
  • Ketoprofen poisoning
  • Naproxen overdose
  • Naproxen poisoning
  • Poisoning caused by propionic acid and/or propionic acid derivative
  • Tiaprofenic acid overdose
  • Tiaprofenic acid poisoning

Coding GuidelinesGuidance

When coding a poisoning or reaction to the improper use of a medication (e.g., overdose, wrong substance given or taken in error, wrong route of administration), first assign the appropriate code from categories T36-T50. The poisoning codes have an associated intent as their 5th or 6th character (accidental, intentional self-harm, assault and undetermined). If the intent of the poisoning is unknown or unspecified, code the intent as accidental intent. The undetermined intent is only for use if the documentation in the record specifies that the intent cannot be determined. Use additional code(s) for all manifestations of poisonings.

The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of nonopioid analgesics, antipyretics and antirheumatics (T39). 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 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

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

CCSR EXT020
External cause codes: intent of injury, accidental/unintentional
Default principal diagnosis: inpatient No · outpatient No
CCSR EXT014
External cause codes: poisoning by drug
Default principal diagnosis: inpatient No · outpatient No
CCSR INJ022
Poisoning by drugs, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Fenoprofen

    a propionic acid derivative that is used as a non-steroidal anti-inflammatory agent.

  • Flurbiprofen

    an anti-inflammatory analgesic and antipyretic of the phenylalkynoic acid series. it has been shown to reduce bone resorption in periodontal disease by inhibiting carbonic anhydrase.

  • Ibuprofen

    a non-steroidal anti-inflammatory agent with analgesic, antipyretic, and anti-inflammatory properties

  • Ketoprofen

    an ibuprofen-type anti-inflammatory analgesic and antipyretic. it is used in the treatment of rheumatoid arthritis and osteoarthritis.

  • Carboxylesterase

    carboxylesterase is a serine-dependent esterase with wide substrate specificity. the enzyme is involved in the detoxification of xenobiotics and the activation of ester and of amide prodrugs.

  • Naproxen

    an anti-inflammatory agent with analgesic and antipyretic properties. both the acid and its sodium salt are used in the treatment of rheumatoid arthritis and other rheumatic or musculoskeletal disorders, dysmenorrhea, and acute gout.

  • Oxaprozin

    an oxazole-propionic acid derivative, cyclooxygenase inhibitor, and non-steroidal anti-inflammatory drug that is used in the treatment of pain and inflammation associated with of osteoarthritis; rheumatoid arthritis; and arthritis, juvenile.

  • Suprofen

    an ibuprofen-type anti-inflammatory analgesic and antipyretic. it inhibits prostaglandin synthesis and has been proposed as an anti-arthritic.

Table of Drugs and ChemicalsClinical

Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.

SubstanceAccidentalSelf-harmAssaultUndeter­minedAdverse
Effect		Under­dosing
CarprofenT39.311T39.312T39.313T39.314T39.315T39.316
EsflurbiprofenT39.311T39.312T39.313T39.314T39.315T39.316
FenoprofenT39.311T39.312T39.313T39.314T39.315T39.316
FlurbiprofenT39.311T39.312T39.313T39.314T39.315T39.316
IbufenacT39.311T39.312T39.313T39.314T39.315T39.316
IbuprofenT39.311T39.312T39.313T39.314T39.315T39.316
IbuproxamT39.311T39.312T39.313T39.314T39.315T39.316
KetoprofenT39.311T39.312T39.313T39.314T39.315T39.316
NaproxenT39.311T39.312T39.313T39.314T39.315T39.316
OxaprozinT39.311T39.312T39.313T39.314T39.315T39.316
SuprofenT39.311T39.312T39.313T39.314T39.315T39.316
Tiaprofenic acidT39.311T39.312T39.313T39.314T39.315T39.316

Patient EducationClinical

Medication Errors

Medicines treat infectious diseases, prevent problems from chronic diseases, and ease pain. But medicines can also cause harmful reactions if not used correctly. Errors can happen in the hospital, at the health care provider's office, at the pharmacy, or at home. You can help prevent errors by:

Read the full article at MedlinePlus

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

Convert T39.311A to ICD-9-CMHistory

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

ICD-9-CM
965.61 Pois-propionic acid derv
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
E850.7 Acc poison-nonnarc analg
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T39.311AOverview

Is T39.311A a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by propionic acid derivatives, accidental (unintentional), initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in T39.311A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for poisoning by propionic acid derivatives, accidental (unintentional), such as an emergency visit or first evaluation.

What MS-DRG does T39.311A group to?

When poisoning by propionic acid derivatives, accidental (unintentional), initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 917, 918, with relative weights from 0.8571 to 1.5684 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of T39.311A?

Under the General Equivalence Mappings, poisoning by propionic acid derivatives, accidental (unintentional), initial encounter converts to ICD-9-CM 965.61 (pois-propionic acid derv) and E850.7 (acc poison-nonnarc analg). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.