2026 ICD-10-CM Diagnosis Code T37.2X3APoisoning by antimalarials and drugs acting on other blood protozoa, assault, initial encounter
T37.2X3A is a billable ICD-10-CM diagnosis code for poisoning by antimalarials and drugs acting on other blood protozoa, assault, 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, assault; External cause codes: poisoning by drug; and Poisoning by drugs, initial encounter.
Code Identity
Code Classification
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
Amodiaquine
a 4-aminoquinoline compound with anti-inflammatory properties.Chloroquine
the prototypical antimalarial agent with a mechanism that is not well understood. it has also been used to treat rheumatoid arthritis, systemic lupus erythematosus, and in the systemic therapy of amebic liver abscesses.Cinchona
a genus of rubiaceous south american trees that yields the toxic cinchona alkaloids from their bark; quinine; quinidine; chinconine, cinchonidine and others are used to treat malaria and cardiac arrhythmias.Cinchona Alkaloids
alkaloids extracted from various species of cinchona.Eflornithine
an inhibitor of ornithine decarboxylase, the rate limiting enzyme of the polyamine biosynthetic pathway.Mefloquine
a phospholipid-interacting antimalarial drug (antimalarials). it is very effective against plasmodium falciparum with very few side effects.Primaquine
an aminoquinoline that is given by mouth to produce a radical cure and prevent relapse of vivax and ovale malarias following treatment with a blood schizontocide. it has also been used to prevent transmission of falciparum malaria by those returning to areas where there is a potential for re-introduction of malaria. adverse effects include anemias and gi disturbances. (from martindale, the extra pharmacopeia, 30th ed, p404)Proguanil
a biguanide compound which metabolizes in the body to form cycloguanil, an anti-malaria agent.Pyrimethamine
one of the folic acid antagonists that is used as an antimalarial or with a sulfonamide to treat toxoplasmosis.Quinacrine
an acridine derivative formerly widely used as an antimalarial but superseded by chloroquine in recent years. it has also been used as an anthelmintic and in the treatment of giardiasis and malignant effusions. it is used in cell biological experiments as an inhibitor of phospholipase a2.Quinacrine Mustard
nitrogen mustard analog of quinacrine used primarily as a stain in the studies of chromosomes and chromatin. fluoresces by reaction with nucleic acids in chromosomes.Quinine
an alkaloid derived from the bark of the cinchona tree. it is used as an antimalarial drug, and is the active ingredient in extracts of the cinchona that have been used for that purpose since before 1633. quinine is also a mild antipyretic and analgesic and has been used in common cold preparations for that purpose. it was used commonly and as a bitter and flavoring agent, and is still useful for the treatment of babesiosis. quinine is also useful in some muscular disorders, especially nocturnal leg cramps and myotonia congenita, because of its direct effects on muscle membrane and sodium channels. the mechanisms of its antimalarial effects are not well understood.
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
Poisoning
A poison is any substance that is harmful to your body. You might swallow it, inhale it, inject it, or absorb it through your skin. Any substance can be poisonous if too much is taken. Poisons can include:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T37.2X3A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T37.2X3AOverview
Is T37.2X3A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by antimalarials and drugs acting on other blood protozoa, assault, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T37.2X3A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for poisoning by antimalarials and drugs acting on other blood protozoa, assault, such as an emergency visit or first evaluation.
What MS-DRG does T37.2X3A group to?
When poisoning by antimalarials and drugs acting on other blood protozoa, assault, 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 T37.2X3A?
Under the General Equivalence Mappings, poisoning by antimalarials and drugs acting on other blood protozoa, assault, initial encounter converts to ICD-9-CM 961.4 (poisoning-antimalarials) and E962.0 (assault-pois w medic agt). 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.
