2026 ICD-10-CM Diagnosis Code T50.4X1APoisoning by drugs affecting uric acid metabolism, accidental (unintentional), initial encounter
T50.4X1A is a billable ICD-10-CM diagnosis code for poisoning by drugs affecting uric acid metabolism, 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. Coders also document this condition as accidental allopurinol overdose. 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 allopurinol overdose
- Accidental allopurinol poisoning
- Accidental colchicine overdose
- Accidental colchicine poisoning
- Accidental probenecid poisoning
- Allopurinol overdose
- Colchicine overdose
- Poisoning by allopurinol
- Poisoning by colchicine
- Poisoning by probenecid
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 diuretics and other and unspecified drugs, medicaments and biological substances (T50). 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
Allopurinol
a xanthine oxidase inhibitor that decreases uric acid production. it also acts as an antimetabolite on some simpler organisms.Benzbromarone
uricosuric that acts by increasing uric acid clearance. it is used in the treatment of gout.Colchicine
a major alkaloid from colchicum autumnale l. and found also in other colchicum species. its primary therapeutic use is in the treatment of gout, but it has been used also in the therapy of familial mediterranean fever (periodic disease).Probenecid
the prototypical uricosuric agent. it inhibits the renal excretion of organic anions and reduces tubular reabsorption of urate. probenecid has also been used to treat patients with renal impairment, and, because it reduces the renal tubular excretion of other drugs, has been used as an adjunct to antibacterial therapy.Sulfinpyrazone
a uricosuric drug that is used to reduce the serum urate levels in gout therapy. it lacks anti-inflammatory, analgesic, and diuretic properties.Urate Oxidase
an enzyme that catalyzes the conversion of urate and unidentified products. it is a copper protein. the initial products decompose to form allantoin. ec 1.7.3.3.
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 T50.4X1A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T50.4X1AOverview
Is T50.4X1A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by drugs affecting uric acid metabolism, accidental (unintentional), initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T50.4X1A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for poisoning by drugs affecting uric acid metabolism, accidental (unintentional), such as an emergency visit or first evaluation.
What MS-DRG does T50.4X1A group to?
When poisoning by drugs affecting uric acid metabolism, 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 T50.4X1A?
Under the General Equivalence Mappings, poisoning by drugs affecting uric acid metabolism, accidental (unintentional), initial encounter converts to ICD-9-CM 974.7 (pois-uric acid metabol) and E858.5 (acc poisn-metabol agnt). 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.
