2026 ICD-10-CM Diagnosis Code T38.1X2APoisoning by thyroid hormones and substitutes, intentional self-harm, initial encounter
T38.1X2A is a billable ICD-10-CM diagnosis code for poisoning by thyroid hormones and substitutes, intentional self-harm, 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, self-harm; 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.
- Intentional levothyroxine poisoning
- Intentional liothyronine overdose
- Intentional liothyronine poisoning
- Intentional thyroglobulin poisoning
- Intentional thyroxin overdose
- Intentional thyroxin poisoning
- Levothyroxine poisoning
- Liothyronine overdose
- Poisoning by liothyronine
- Poisoning by thyroglobulin
- Thyroid hormone overdose
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 hormones and their synthetic substitutes and antagonists, not elsewhere classified (T38). 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
Correspondence as Topic
works on written communication between persons or between institutions or organizations.Histiocytosis, Langerhans-Cell
a group of disorders resulting from the abnormal proliferation of and tissue infiltration by langerhans cells which can be detected by their characteristic birbeck granules (x bodies), or by monoclonal antibody staining for their surface cd1 antigens. langerhans-cell granulomatosis can involve a single organ, or can be a systemic disorder.Letter
work consisting of written or printed communication between individuals or between persons and representatives of corporate bodies. the correspondence may be personal or professional. in medical and other scientific publications the letter is usually from one or more authors to the editor of the journal or book publishing the item being commented upon or discussed. letter is often accompanied by comment.Thyroglobulin
tumors or cancer of the thymus gland.Iodide Peroxidase
a hemeprotein that catalyzes the oxidation of the iodide radical to iodine with the subsequent iodination of many organic compounds, particularly proteins. ec 1.11.1.8.Receptors, Thyroid Hormone
specific high affinity binding proteins for thyroid hormones in target cells. they are usually found in the nucleus and regulate dna transcription. these receptors are activated by hormones that leads to transcription, cell differentiation, and growth suppression. thyroid hormone receptors are encoded by two genes (genes, erba): erba-alpha and erba-beta for alpha and beta thyroid hormone receptors, respectively.Thyroxine
the major hormone derived from the thyroid gland. thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. thyroxine is peripherally deiodinated to form triiodothyronine which exerts a broad spectrum of stimulatory effects on cell metabolism.Thyroxine-Binding Globulin
a thyroid hormone transport protein found in serum. it binds about 75% of circulating thyroxine and 70% of circulating triiodothyronine.Thyroxine-Binding Proteins
blood proteins that bind to thyroid hormones such as thyroxine and transport them throughout the circulatory system.Thyroid Hormone-Binding Proteins
membrane-bound proteins found in the endoplasmic reticulum of cultured cells and neoplasms. they were identified originally based on their capacity to bind thyroid hormone.Triiodothyronine
a t3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (t4). most t3 is derived from peripheral monodeiodination of t4 at the 5' position of the outer ring of the iodothyronine nucleus. the hormone finally delivered and used by the tissues is mainly t3.Triiodothyronine, Reverse
a metabolite of thyroxine, formed by the peripheral enzymatic monodeiodination of t4 at the 5 position of the inner ring of the iodothyronine nucleus.
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
Hormones
Hormones are your body's chemical messengers. They travel in your bloodstream to tissues or organs. They work slowly, over time, and affect many different processes, including:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T38.1X2A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T38.1X2AOverview
Is T38.1X2A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by thyroid hormones and substitutes, intentional self-harm, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T38.1X2A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for poisoning by thyroid hormones and substitutes, intentional self-harm, such as an emergency visit or first evaluation.
What MS-DRG does T38.1X2A group to?
When poisoning by thyroid hormones and substitutes, intentional self-harm, 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 T38.1X2A?
Under the General Equivalence Mappings, poisoning by thyroid hormones and substitutes, intentional self-harm, initial encounter converts to ICD-9-CM 962.7 (poisoning-thyroid/deriv) and E950.4 (poison-drug/medicin 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.
