2027 ICD-10-CM Diagnosis Code T61.8X1AToxic effect of other seafood, accidental (unintentional), initial encounter

ICD-10-CM Codes›S00–T88›T51-T65›T61

ICD-10-CM T61.8X1A
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T61.8X1A is a billable ICD-10-CM diagnosis code for toxic effect of other seafood, 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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 917 through 918. Coders also document this condition as jellyfish poisoning. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under External cause codes: intent of injury, accidental/unintentional; External cause codes: poisoning by non-drug; and Toxic effects, initial encounter.

Code Identity

ICD-10-CM Code
T61.8X1A
Billable Status
Yes — Valid for Submission
Code Describes
Toxic effect of other seafood, accidental (unintentional), initial encounter
Short Description
Toxic effect of seafood, accidental (unintentional), init
Parent Code
T61.8X1
Toxic effect of other seafood, accidental (unintentional)

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT51-T65Toxic effects of substances chiefly nonmedicinal as to source
CategoryT61Toxic effect of noxious substances eaten as seafood
This CodeT61.8X1AToxic effect of other seafood, accidental (unintentional), initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Jellyfish poisoning

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Toxic effect of noxious substances eaten as seafood (T61). 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 T61.8X1A: its own notes plus those printed at T61, block T51-T65, 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 T61 Toxic effect of noxious substances eaten as seafood applies to 72 codes
  • allergic reaction to food, such as:
  • anaphylactic reaction or shock due to adverse food reaction (T78.0-)
  • bacterial foodborne intoxications (A05.-)
  • dermatitis (L23.6, L25.4, L27.2)
  • food protein-induced enterocolitis syndrome (K52.21)
  • food protein-induced enteropathy (K52.22)
  • gastroenteritis (noninfective) (K52.29)
  • toxic effect of aflatoxin and other mycotoxins (T64)
  • toxic effect of cyanides (T65.0-)
  • toxic effect of harmful algae bloom (T65.82-)
  • toxic effect of hydrogen cyanide (T57.3-)
  • toxic effect of mercury (T56.1-)
  • toxic effect of red tide (T65.82-)
From Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • contact with and (suspected) exposure to toxic substances (Z77.-)

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 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 Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • code(s):
  • for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70)
  • personal history of foreign body fully removed (Z87.821)
  • to identify any retained foreign body, if applicable (Z18.-)
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 Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • When no intent is indicated code to accidental. Undetermined intent is only for use when there is specific documentation in the record that the intent of the toxic effect cannot be determined.
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 T61 Toxic effect of noxious substances eaten as seafood applies to 72 codes
  • The appropriate 7th character is to be added to each code from category T61
Values for category T61 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 T61.8X1A, its category, or a range that includes it.

Excludes2 2

These codes carry an Excludes2 note naming T61.8X1A: its condition is not part of those codes, and both may be reported when the patient has both.

  • T63 Toxic effect of contact with venomous animals and plants
    ingestion of toxic animal or plant (T61.-, T62.-) names T61.-, which includes this code
  • T63.5 Toxic effect of contact with venomous fish
    poisoning by ingestion of fish (T61.-) names T61.-, which includes this code

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 EXT015
External cause codes: poisoning by non-drug
Default principal diagnosis: inpatient No · outpatient No
CCSR INJ023
Toxic effects, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

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
Food, foodstuffs, noxious, nonbacterial, NEC::seafood::specified NECT61.8X1T61.8X2T61.8X3T61.8X4––
Seafood::specified NECT61.8X1T61.8X2T61.8X3T61.8X4––

Patient EducationClinical

Foodborne Illness

Each year, around 48 million people in the United States get sick from contaminated food. Common causes include bacteria and viruses. Less often, the cause may be a parasite or a harmful chemical, such as a high amount of pesticides. Symptoms of foodborne illness depend on the cause. They can be mild or serious. They usually include:

Read the full article at MedlinePlus

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

Convert T61.8X1A to ICD-9-CMHistory

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

ICD-9-CM
988.0 Toxic eff fish/shellfish
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
E865.2 Acc poison-fish NEC
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About T61.8X1AOverview

Is T61.8X1A (Toxic effect of other seafood, accidental (unintentional)) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of other seafood, accidental (unintentional), initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in T61.8X1A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for toxic effect of other seafood, accidental (unintentional), such as an emergency visit or first evaluation.

What MS-DRG does T61.8X1A group to?

When toxic effect of other seafood, accidental (unintentional), initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 918, 917, with relative weights from 0.8716 to 1.5698 depending on complications. Higher weights mean higher Medicare reimbursement.

Can T61.8X1A be reported with a code from T78.0?

Not as a rule. The Excludes1 note at T61, which applies to T61.8X1A, lists "anaphylactic reaction or shock due to adverse food reaction (T78.0-)". 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).

What is the ICD-9 equivalent of T61.8X1A?

Under the General Equivalence Mappings, toxic effect of other seafood, accidental (unintentional), initial encounter converts to ICD-9-CM 988.0 (toxic eff fish/shellfish) and E865.2 (acc poison-fish NEC). The mapping is approximate, so confirm the match fits the documentation.