2026 ICD-10-CM Diagnosis Code T38.994APoisoning by other hormone antagonists, undetermined, initial encounter
T38.994A is a billable ICD-10-CM diagnosis code for poisoning by other hormone antagonists, undetermined, 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, undetermined; External cause codes: poisoning by drug; and Poisoning by drugs, initial encounter.
Code Identity
Code Classification
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
Octreotide
a potent, long-acting synthetic somatostatin octapeptide analog that inhibits secretion of growth hormone and is used to treat hormone-secreting tumors; diabetes mellitus; hypotension, orthostatic; hyperinsulinism; hypergastrinemia; and small bowel fistula.Receptors, Somatostatin
cell surface proteins that bind somatostatin and trigger intracellular changes which influence the behavior of cells. somatostatin is a hypothalamic hormone, a pancreatic hormone, and a central and peripheral neurotransmitter. activated somatostatin receptors on pituitary cells inhibit the release of growth hormone; those on endocrine and gastrointestinal cells regulate the absorption and utilization of nutrients; and those on neurons mediate somatostatin's role as a neurotransmitter.Somatostatin
a 14-amino acid peptide named for its ability to inhibit pituitary growth hormone release, also called somatotropin release-inhibiting factor. it is expressed in the central and peripheral nervous systems, the gut, and other organs. srif can also inhibit the release of thyroid-stimulating hormone; prolactin; insulin; and glucagon besides acting as a neurotransmitter and neuromodulator. in a number of species including humans, there is an additional form of somatostatin, srif-28 with a 14-amino acid extension at the n-terminal.Somatostatin-28
a 28-amino acid peptide with the same biological activities of somatostatin-14 but with a 14-amino acid extension at the n-terminal. srif-28 is the major form of somatostatin in the gastrointestinal tract.Somatostatinoma
a somatostatin-secreting tumor derived from the pancreatic delta cells (somatostatin-secreting cells). it is also found in the intestine. somatostatinomas are associated with diabetes mellitus; cholelithiasis; steatorrhea; and hypochlorhydria. the majority of somatostatinomas have the potential for metastasis.Somatostatin-Secreting Cells
endocrine cells found throughout the gastrointestinal tract and in islets of the pancreas. d cells secrete somatostatin that acts in both an endocrine and paracrine manner. somatostatin acts on a variety of tissues including the pituitary gland; gastrointestinal tract; pancreas; and kidney by inhibiting the release of hormones, such as growth hormone; gastrin; insulin; and renin.
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 T38.994A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T38.994AOverview
Is T38.994A (Poisoning by other hormone antagonists, undetermined) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by other hormone antagonists, undetermined, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T38.994A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for poisoning by other hormone antagonists, undetermined, such as an emergency visit or first evaluation.
What MS-DRG does T38.994A group to?
When poisoning by other hormone antagonists, undetermined, 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 T38.994A?
Under the General Equivalence Mappings, poisoning by other hormone antagonists, undetermined, initial encounter converts to ICD-9-CM 962.9 (poisoning hormon NEC/NOS) and E980.4 (undet pois-med agnt 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.
