2026 ICD-10-CM Diagnosis Code T38.1X3SPoisoning by thyroid hormones and substitutes, assault, sequela
T38.1X3S is a billable ICD-10-CM diagnosis code for poisoning by thyroid hormones and substitutes, 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. 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
T38.1X3S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
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 T38.1X3S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T38.1X3SOverview
Is T38.1X3S (Poisoning by thyroid hormones and substitutes, assault) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by thyroid hormones and substitutes, assault, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T38.1X3S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by thyroid hormones and substitutes, assault itself has resolved, not the original event.
What MS-DRG does T38.1X3S group to?
When poisoning by thyroid hormones and substitutes, 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 T38.1X3S 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 thyroid hormones and substitutes, assault, sequela on inpatient claims.
What is the ICD-9 equivalent of T38.1X3S?
Under the General Equivalence Mappings, poisoning by thyroid hormones and substitutes, 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.
