2026 ICD-10-CM Diagnosis Code T50.Z13SPoisoning by immunoglobulin, assault, sequela
T50.Z13S is a billable ICD-10-CM diagnosis code for poisoning by immunoglobulin, assault, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 922 through 923. The code is exempt from POA reporting. Coders also document this condition as excessive dose of antiserum administered. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Poisoning/toxic effect/adverse effects/underdosing, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
T50.Z13S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Excessive dose of antiserum administered
- Excessive dose of gamma globulin administered
- Intentional excessive dose of antiserum administered
- Intentional excessive dose of gamma globulin administered
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
Diphtheria
a localized infection of mucous membranes or skin caused by toxigenic strains of corynebacterium diphtheriae. it is characterized by the presence of a pseudomembrane at the site of infection. diphtheria toxin, produced by c. diphtheriae, can cause myocarditis, polyneuritis, and other systemic toxic effects.Diphtheria Antitoxin
an antitoxin produced against the toxin of corynebacterium diphtheriae that is used for the treatment of diphtheria.Diphtheria Toxin
an adp-ribosylating polypeptide produced by corynebacterium diphtheriae that causes the signs and symptoms of diphtheria. it can be broken into two unequal domains: the smaller, catalytic a domain is the lethal moiety and contains mono(adp-ribose) transferases which transfers adp ribose to peptide elongation factor 2 thereby inhibiting protein synthesis; and the larger b domain that is needed for entry into cells.Diphtheria Toxoid
the formaldehyde-inactivated toxin of corynebacterium diphtheriae. it is generally used in mixtures with tetanus toxoid and pertussis vaccine; (dtp); or with tetanus toxoid alone (dt for pediatric use and td, which contains 5- to 10-fold less diphtheria toxoid, for other use). diphtheria toxoid is used for the prevention of diphtheria; diphtheria antitoxin is for treatment.Diphtheria-Tetanus Vaccine
a combined vaccine used to prevent infection with diphtheria and tetanus toxoid. this is used in place of dtp vaccine (diphtheria-tetanus-pertussis vaccine) when pertussis vaccine is contraindicated.Diphtheria-Tetanus-acellular Pertussis Vaccines
combined vaccines consisting of diphtheria toxoid; tetanus toxoid; and an acellular form of pertussis vaccine. at least five different purified antigens of b. pertussis have been used in various combinations in these vaccines.Diphtheria-Tetanus-Pertussis Vaccine
a vaccine consisting of diphtheria toxoid; tetanus toxoid; and whole-cell pertussis vaccine. the vaccine protects against diphtheria, tetanus, and whooping cough.Fowlpox
a poxvirus infection of poultry and other birds characterized by the formation of wart-like nodules on the skin and diphtheritic necrotic masses (cankers) in the upper digestive and respiratory tracts.Heparin-binding EGF-like Growth Factor
an egf family member that is expressed in a variety of hematopoietic, endothelial, vascular smooth muscle, and epithelial cells. it is synthesized as a transmembrane protein which is cleaved by proteases to produce the secreted form of the protein which has specificity for the egf receptor and the erbb-4 receptor. the membrane-bound form of the protein has been identified as the receptor which binds to and allows diphtheria toxin to enter cells.Hepatitis B
inflammation of the liver in humans caused by a member of the orthohepadnavirus genus, hepatitis b virus. it is primarily transmitted by parenteral exposure, such as transfusion of contaminated blood or blood products, but can also be transmitted via sexual or intimate personal contact.Hepatitis B Antibodies
antibodies to the hepatitis b antigens, including antibodies to the surface (australia) and core of the dane particle and those to the e antigens.Hepatitis B Antigens
antigens of the virion of the hepatitis b virus or the dane particle, its surface (hepatitis b surface antigens), core (hepatitis b core antigens), and other associated antigens, including the hepatitis b e antigens.Hepatitis B Core Antigens
the hepatitis b antigen within the core of the dane particle, the infectious hepatitis virion.Hepatitis B e Antigens
a closely related group of antigens found in the plasma only during the infective phase of hepatitis b or in virulent chronic hepatitis b, probably indicating active virus replication; there are three subtypes which may exist in a complex with immunoglobulins g.Hepatitis B Surface Antigens
those hepatitis b antigens found on the surface of the dane particle and on the 20 nm spherical and tubular particles. several subspecificities of the surface antigen are known. these were formerly called the australia antigen.Hepatitis B Vaccines
vaccines or candidate vaccines containing inactivated hepatitis b or some of its component antigens and designed to prevent hepatitis b. some vaccines may be recombinantly produced.Hepatitis B virus
the type species of the genus orthohepadnavirus which causes human hepatitis b and is also apparently a causal agent in human hepatocellular carcinoma. the dane particle is an intact hepatitis virion, named after its discoverer. non-infectious spherical and tubular particles are also seen in the serum.Hepatitis B Virus, Duck
a dna virus that closely resembles human hepatitis b virus. it has been recovered from naturally infected ducks.Hepatitis B Virus, Woodchuck
an orthohepadnavirus causing chronic liver disease and hepatocellular carcinoma in woodchucks. it closely resembles the human hepatitis b virus.Hepatitis B, Chronic
inflammation of the liver in humans caused by hepatitis b virus lasting six months or more. it is primarily transmitted by parenteral exposure, such as transfusion of contaminated blood or blood products, but can also be transmitted via sexual or intimate personal contact.Orthohepadnavirus
a genus of hepadnaviridae causing hepatitis in humans, woodchucks (hepatitis b virus, woodchuck) and ground squirrels. hepatitis b virus is the type species.Rabies
acute viral cns infection affecting mammals, including humans. it is caused by rabies virus and usually spread by contamination with virus-laden saliva of bites inflicted by rabid animals. important animal vectors include the dog, cat, bat, fox, raccoon, skunk, and wolf.Rabies Vaccines
vaccines or candidate vaccines used to prevent and treat rabies. the inactivated virus vaccine is used for preexposure immunization to persons at high risk of exposure, and in conjunction with rabies immunoglobulin, for postexposure prophylaxis.Rabies virus
the type species of lyssavirus causing rabies in humans and other animals. transmission is mostly by animal bites through saliva. the virus is neurotropic multiplying in neurons and myotubes of vertebrates.
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 T50.Z13S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T50.Z13SOverview
Is T50.Z13S (Poisoning by immunoglobulin, assault) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by immunoglobulin, assault, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T50.Z13S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by immunoglobulin, assault itself has resolved, not the original event.
What MS-DRG does T50.Z13S group to?
When poisoning by immunoglobulin, assault, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T50.Z13S exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for poisoning by immunoglobulin, assault, sequela on inpatient claims.
What is the ICD-9 equivalent of T50.Z13S?
Under the General Equivalence Mappings, poisoning by immunoglobulin, assault, sequela converts to ICD-9-CM 909.0 (late eff drug poisoning) and E969 (late effect assault). 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.
