2026 ICD-10-CM Diagnosis Code T45.3X1SPoisoning by enzymes, accidental (unintentional), sequela
T45.3X1S is a billable ICD-10-CM diagnosis code for poisoning by enzymes, accidental (unintentional), 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 accidental penicillinase poisoning. 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
T45.3X1S 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.
- Accidental penicillinase poisoning
- Accidental streptodornase poisoning
- Enzyme overdose
- Poisoning by enzyme
- Poisoning by penicillinase
- Poisoning by streptodornase
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 primarily systemic and hematological agents, not elsewhere classified (T45). 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
Bromelains
protein-digesting and milk-clotting enzymes found in pineapple fruit juice and stem tissue. enzymes from the two sources are distinguished as fruit bromelain and stem bromelain. this enzyme was formerly listed as ec 3.4.22.4.Acatalasia
a rare autosomal recessive disorder resulting from the absence of catalase activity. though usually asymptomatic, a syndrome of oral ulcerations and gangrene may be present.Catalase
an oxidoreductase that catalyzes the conversion of hydrogen peroxide to water and oxygen. it is present in many animal cells. a deficiency of this enzyme results in acatalasia.Chymopapain
a cysteine endopeptidase isolated from papaya latex. preferential cleavage at glutamic and aspartic acid residues. ec 3.4.22.6.Chymases
a family of neutral serine proteases with chymotrypsin-like activity. chymases are primarily found in the secretory granules of mast cells and are released during mast cell degranulation.Chymotrypsin
a serine endopeptidase secreted by the pancreas as its zymogen, chymotrypsinogen and carried in the pancreatic juice to the duodenum where it is activated by trypsin. it selectively cleaves aromatic amino acids on the carboxyl side.Chymotrypsinogen
a serine endopeptidase secreted by the pancreas as its zymogen, chymotrypsinogen and carried in the pancreatic juice to the duodenum where it is activated by trypsin. it selectively cleaves aromatic amino acids on the carboxyl side.Coronavirus 3C Proteases
3c proteases that occur in species of coronaviridae.Penicillinase
a beta-lactamase preferentially cleaving penicillins. (dorland, 28th ed) ec 3.5.2.-.Pronase
a proteolytic enzyme obtained from streptomyces griseus.alpha 1-Antitrypsin
plasma glycoprotein member of the serpin superfamily which inhibits trypsin; neutrophil elastase; and other proteolytic enzymes.Aprotinin
a single-chain polypeptide derived from bovine tissues consisting of 58 amino-acid residues. it is an inhibitor of proteolytic enzymes including chymotrypsin; kallikrein; plasmin; and trypsin. it is used in the treatment of hemorrhage associated with raised plasma concentrations of plasmin. it is also used to reduce blood loss and transfusion requirements in patients at high risk of major blood loss during and following open heart surgery with extracorporeal circulation. (reynolds jef(ed): martindale: the extra pharmacopoeia (electronic version). micromedex, inc, englewood, co, 1995)Receptor, PAR-2
a g-protein-coupled, proteinase-activated receptor that is expressed in a variety of tissues including endothelium; leukocytes; and the gastrointestinal tract. the receptor is activated by trypsin, which cleaves off the n-terminal peptide from the receptor. the new n-terminal peptide is a cryptic ligand for the receptor. the uncleaved receptor can also be activated by the n-terminal peptide present on the activated thrombin receptor and by small synthetic peptides that contain the unmasked n-terminal sequence.Trypsin
a serine endopeptidase that is formed from trypsinogen in the pancreas. it is converted into its active form by enteropeptidase in the small intestine. it catalyzes hydrolysis of the carboxyl group of either arginine or lysine. ec 3.4.21.4.Trypsin Inhibitor, Bowman-Birk Soybean
a low-molecular-weight protein (minimum molecular weight 8000) which has the ability to inhibit trypsin as well as chymotrypsin at independent binding sites. it is characterized by a high cystine content and the absence of glycine.Trypsin Inhibitor, Kazal Pancreatic
a secreted kazal motif-containing serine peptidase inhibitor that inhibits trypsin. it is a protein composed of 56 amino acid residues and is different in amino acid composition and physiological activity from the kunitz bovine pancreatic trypsin inhibitor (aprotinin). it protects against the trypsin-mediated premature activation of enzyme precursors in the pancreas. mutations in the spink1 gene are associated with chronic pancreatitis.Trypsin Inhibitor, Kunitz Soybean
a high-molecular-weight protein (approximately 22,500) containing 198 amino acid residues. it is a strong inhibitor of trypsin and human plasmin.Trypsin Inhibitors
serine proteinase inhibitors which inhibit trypsin. they may be endogenous or exogenous compounds.Trypsinogen
the inactive proenzyme of trypsin secreted by the pancreas, activated in the duodenum via cleavage by enteropeptidase. (stedman, 25th ed)
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 T45.3X1S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T45.3X1SOverview
Is T45.3X1S (Poisoning by enzymes, accidental (unintentional)) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by enzymes, accidental (unintentional), sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T45.3X1S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by enzymes, accidental (unintentional) itself has resolved, not the original event.
What MS-DRG does T45.3X1S group to?
When poisoning by enzymes, accidental (unintentional), 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 T45.3X1S 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 enzymes, accidental (unintentional), sequela on inpatient claims.
What is the ICD-9 equivalent of T45.3X1S?
Under the General Equivalence Mappings, poisoning by enzymes, accidental (unintentional), sequela converts to ICD-9-CM 909.0 (late eff drug poisoning) and E929.2 (late eff acc poisoning). 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.
