2026 ICD-10-CM Diagnosis Code T37.8X1APoisoning by other specified systemic anti-infectives and antiparasitics, accidental (unintentional), initial encounter
T37.8X1A is a billable ICD-10-CM diagnosis code for poisoning by other specified systemic anti-infectives and antiparasitics, 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
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Accidental diiodohydroxyquinoline poisoning
- Accidental flucytosine overdose
- Accidental flucytosine poisoning
- Accidental hydroxyquinoline overdose
- Accidental hydroxyquinoline poisoning
- Accidental sulfamethoxazole and/or trimethoprim overdose
- Accidental sulfamethoxazole and/or trimethoprim poisoning
- Accidental trimethoprim overdose
- Accidental trimethoprim poisoning
- Flucytosine overdose
- Hydroxyquinoline overdose
- Hydroxyquinoline poisoning
- Nitrofuran derivative overdose
- Poisoning by chiniofon
- Poisoning by diiodohydroxyquin
- Poisoning by flucytosine
- Poisoning by nitrofuran derivatives
- Poisoning caused by quinoline
- Sulfamethoxazole and/or trimethoprim overdose
- Trimethoprim overdose
- Trimethoprim 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 other systemic anti-infectives and antiparasitics (T37). 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.
Clinical InformationClinical
Bithionol
halogenated anti-infective agent that is used against trematode and cestode infestations.Cinoxacin
synthetic antimicrobial related to oxolinic acid and nalidixic acid and used in urinary tract infections.Clioquinol
a potentially neurotoxic 8-hydroxyquinoline derivative long used as a topical anti-infective, intestinal antiamebic, and vaginal trichomonacide. the oral preparation has been shown to cause subacute myelo-optic neuropathy and has been banned worldwide.Fluconazole
triazole antifungal agent that is used to treat oropharyngeal candidiasis and cryptococcal meningitis in aids.Flucytosine
a fluorinated cytosine analog that is used as an antifungal agent.Furazolidone
a nitrofuran derivative with antiprotozoal and antibacterial activity. furazolidone acts by gradual inhibition of monoamine oxidase. (from martindale, the extra pharmacopoeia, 30th ed, p514)Hexetidine
a bactericidal and fungicidal antiseptic. it is used as a 0.1% mouthwash for local infections and oral hygiene. (from martindale, the extra pharmacopoeia, 30th ed, p797)Hydroxychloroquine
a chemotherapeutic agent that acts against erythrocytic forms of malarial parasites. hydroxychloroquine appears to concentrate in food vacuoles of affected protozoa. it inhibits plasmodial heme polymerase. (from gilman et al., goodman and gilman's the pharmacological basis of therapeutics, 9th ed, p970)Iodoquinol
one of the halogenated 8-quinolinols widely used as an intestinal antiseptic, especially as an antiamebic agent. it is also used topically in other infections and may cause cns and eye damage. it is known by very many similar trade names world-wide.Itraconazole
a triazole antifungal agent that inhibits cytochrome p-450-dependent enzymes required for ergosterol synthesis.Diatrizoate Meglumine
a versatile contrast medium used for diagnostic x-ray radiology.Iothalamate Meglumine
a radiopaque medium used for urography, angiography, venography, and myelography. it is highly viscous and binds to plasma proteins.Ioxaglic Acid
a low-osmolar, ionic contrast medium used in various radiographic procedures.Meglumine
1-deoxy-1-(methylamino)-d-glucitol. a derivative of sorbitol in which the hydroxyl group in position 1 is replaced by a methylamino group. often used in conjunction with iodinated organic compounds as contrast medium.Meglumine Antimoniate
antimony salt of meglumine that is used in the treatment of leishmaniasis.Metronidazole
a nitroimidazole used to treat amebiasis; vaginitis; trichomonas infections; giardiasis; anaerobic bacteria; and treponemal infections.Nalidixic Acid
a synthetic 1,8-naphthyridine antimicrobial agent with a limited bacteriocidal spectrum. it is an inhibitor of the a subunit of bacterial dna gyrase.Nifuratel
local antiprotozoal and antifungal agent that may also be given orally.Nitrofurantoin
a urinary anti-infective agent effective against most gram-positive and gram-negative organisms. although sulfonamides and antibiotics are usually the agents of choice for urinary tract infections, nitrofurantoin is widely used for prophylaxis and long-term suppression.Oxolinic Acid
synthetic antimicrobial related to nalidixic acid and used in urinary tract infections.Pefloxacin
a synthetic broad-spectrum fluoroquinolone antibacterial agent active against most gram-negative and gram-positive bacteria.Pipemidic Acid
antimicrobial against gram negative and some gram positive bacteria. it is protein bound and concentrated in bile and urine and used for gastrointestinal, biliary, and urinary infections.Piromidic Acid
antibacterial against mainly gram negative organisms. it is used for urinary tract and intestinal infections.Trimethoprim
a pyrimidine inhibitor of dihydrofolate reductase, it is an antibacterial related to pyrimethamine. it is potentiated by sulfonamides and the trimethoprim, sulfamethoxazole drug combination is the form most often used. it is sometimes used alone as an antimalarial. trimethoprim resistance has been reported.Trimethoprim Resistance
nonsusceptibility of bacteria to the action of trimethoprim.Trimethoprim, Sulfamethoxazole Drug Combination
a drug combination with broad-spectrum antibacterial activity against both gram-positive and gram-negative organisms. it is effective in the treatment of many infections, including pneumocystis pneumonia in aids.
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
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 T37.8X1A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T37.8X1AOverview
Is T37.8X1A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by other specified systemic anti-infectives and antiparasitics, accidental (unintentional), initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T37.8X1A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for poisoning by other specified systemic anti-infectives and antiparasitics, accidental (unintentional), such as an emergency visit or first evaluation.
What MS-DRG does T37.8X1A group to?
When poisoning by other specified systemic anti-infectives and antiparasitics, 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 T37.8X1A?
Under the General Equivalence Mappings, poisoning by other specified systemic anti-infectives and antiparasitics, accidental (unintentional), initial encounter converts to ICD-9-CM 961.9 (pois-anti-infect NEC/NOS) and E857 (acc pois-oth anti-infect). 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.
