2027 ICD-10-CM Diagnosis Code T61.01XACiguatera fish poisoning, accidental (unintentional), initial encounter
T61.01XA is a billable ICD-10-CM diagnosis code for ciguatera fish poisoning, 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 ciguatoxin causing toxic effect. 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
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Ciguatoxin causing toxic effect
- Peripheral neuropathy caused by ciguatoxin
- Peripheral neuropathy caused by toxin
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 T61.01XA: 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.
- 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-)
- 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.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Notes
General instructions on how these codes are used.
- 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.
- 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.
- The appropriate 7th character is to be added to each code from category T61
- 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 T61.01XA, its category, or a range that includes it.
Excludes2 2
These codes carry an Excludes2 note naming T61.01XA: its condition is not part of those codes, and both may be reported when the patient has both.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Ciguatera Poisoning
poisoning caused by ingestion of seafood containing microgram levels of ciguatoxins. the poisoning is characterized by gastrointestinal, neurological and cardiovascular disturbances.
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.
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 T61.01XA to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T61.01XAOverview
Is T61.01XA (Ciguatera fish poisoning, accidental (unintentional)) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report ciguatera fish poisoning, accidental (unintentional), initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in T61.01XA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for ciguatera fish poisoning, accidental (unintentional), such as an emergency visit or first evaluation.
What MS-DRG does T61.01XA group to?
When ciguatera fish poisoning, 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 T61.01XA be reported with a code from T78.0?
Not as a rule. The Excludes1 note at T61, which applies to T61.01XA, 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 T61.01XA?
Under the General Equivalence Mappings, ciguatera fish poisoning, 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.
