2026 ICD-10-CM Diagnosis Code T50.6X5AAdverse effect of antidotes and chelating agents, initial encounter
T50.6X5A is a billable ICD-10-CM diagnosis code for adverse effect of antidotes and chelating agents, 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. The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Adverse effects of drugs and medicaments, initial encounter.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T50.6X5A.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acetylcholinesterase reactivator adverse reaction
- Aldehyde dehydrogenase inhibitor adverse reaction
- Antidote adverse reaction
- Antidotes for pesticides adverse reaction
- Benzodiazepine antagonist adverse reaction
- Chelating agent adverse reaction
- Chronic drug-induced renal disease
- Dicobalt edetate adverse reaction
- Digoxin specific antibody adverse reaction
- Disodium edetate adverse reaction
- Disulfiram adverse reaction
- Drug-induced myasthenia
- Drug-induced pseudoxanthoma elasticum
- Edetate adverse reaction
- Flumazenil adverse reaction
- Hydrofluoric acid burn antidote adverse reaction
- Ion exchange resin adverse reaction
- Penicillamine adverse reaction
- Penicillamine nephropathy
- Penicillamine-induced myasthenia
- Pralidoxime adverse reaction
- Pseudoxanthoma elasticum
- Pseudoxanthoma elasticum caused by penicillamine
- Sodium nitrite adverse reaction
- Sodium thiosulfate adverse reaction
- Toxic neuromuscular junction disorder
- Trisodium edetate adverse reaction
Coding GuidelinesGuidance
When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug.
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
Pseudoxanthoma Elasticum
an inherited disorder of connective tissue with extensive degeneration and calcification of elastic tissue primarily in the skin, eye, and vasculature. at least two forms exist, autosomal recessive and autosomal dominant. this disorder is caused by mutations of one of the atp-binding cassette transporters. patients are predisposed to myocardial infarction and gastrointestinal hemorrhage.ABCC6 wt Allele|ABC34|ARA|ATP-Binding Cassette, Sub-Family C (CFTR/MRP), Member 6 wt Allele|ATP-Binding Cassette, Subfamily C, Member 6 Gene|EST349056|GACI2|MLP1|MOAT-E|MOATE|MRP6|PXE|PXE1|Pseudoxanthoma Elasticum Gene|URG7
human abcc6 wild-type allele is located in the vicinity of 16p13.1 and is approximately 75 kb in length. this allele, which encodes multidrug resistance-associated protein 6, plays a role in the active transport of drugs across the plasma membrane. mutation of the gene is associated with pseudoxanthoma elasticum and generalized arterial calcification of infancy type 2.Pseudoxanthoma Elasticum
a rare, progressive, autosomal recessive inherited disorder caused by mutations in the abcc6 gene. it is characterized by calcification and fragmentation of the elastic fibers of the skin, retina, and cardiovascular system. signs and symptoms include skin plaques and bumps, thickened skin, retinal hemorrhage and obstruction of the blood vessels.Spastic Paraplegia 56|Autosomal Recessive Spastic Paraplegia-56 with or without Pseudoxanthoma Elasticum|SPG56
an autosomal recessive subtype of hereditary spastic paraplegia caused by mutation(s) in the cyp2u1 gene, encoding cytochrome p450 2u1.
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
Drug Reactions
Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions, such as drug interactions, side effects, and allergies.
The full article covers:
- What is a drug interaction?
- What are side effects?
- What are drug allergies?
- How can I stay safe when taking medicines?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T50.6X5A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T50.6X5AOverview
Is T50.6X5A (Adverse effect of antidotes and chelating agents) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of antidotes and chelating agents, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T50.6X5A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for adverse effect of antidotes and chelating agents, such as an emergency visit or first evaluation.
What MS-DRG does T50.6X5A group to?
On inpatient claims, adverse effect of antidotes and chelating agents, initial encounter maps to MS-DRG 917, 918, with relative weights from 0.8571 to 1.5684 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T50.6X5A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of antidotes and chelating agents, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
What is the ICD-9 equivalent of T50.6X5A?
Under the General Equivalence Mappings, adverse effect of antidotes and chelating agents, initial encounter converts to ICD-9-CM 995.29 (adv eff med/biol NEC/NOS) and E947.2 (adv eff antidotes NEC). 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.
