T38.1X1A is the authoritative medical code for Poisoning by thyroid hormones and substitutes, accidental (unintentional), initial encounter. This classification is used in medical billing and clinical recording to specify the clinical criteria for poisoning by thyroid hormones and substitutes, accidental (unintentional), initial encounter (ICD-10-CM T38.1X1A), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Poisoning by thyroid hormones and substitutes, accidental (unintentional), initial encounter is a billable ICD-10-CM diagnosis code T38.1X1A. Includes: adverse effect of correct substance properly administered; poisoning by overdose of substance; poisoning by wrong substance given or taken in error; underdosing by (inadvertently) deliberately taking less substance than prescribed or instructed. Inclusion terms: Poisoning by thyroid hormones and substitutes NOS. Excludes1 (not coded here): mineralocorticoids and their antagonists T50.0-; oxytocic hormones T48.0-; parathyroid hormones and derivatives T50.9-; toxic reaction to local anesthesia in pregnancy O29.3-. Excludes2 (not included here): abuse and dependence of psychoactive substances F10-F19; abuse of non-dependence-producing substances F55.-; immunodeficiency due to drugs D84.821; drug reaction and poisoning affecting newborn P00-P96; pathological drug intoxication inebriation F10-F19. Code first: , for adverse effects, the nature of the adverse effect, such as:; adverse effect NOS T88.7; aspirin gastritis K29.-; blood disorders D56-D76; contact dermatitis L23-L25; dermatitis due to substances taken internally L27.-; nephropathy N14.0-N14.2. Use additional code: code(s) to specify:; manifestations of poisoning; underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9); underdosing of medication regimen (Z91.12-, Z91.13-). 7th character: The appropriate 7th character is to be added to each code from category T38.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for T38.1X1A in the official ICD-10-CM tabular list.
Includes
Conditions the official ICD-10-CM tabular list includes under this code.
- adverse effect of correct substance properly administered
- poisoning by overdose of substance
- poisoning by wrong substance given or taken in error
- underdosing by (inadvertently) deliberately taking less substance than prescribed or instructed
Inclusion Terms
Alternative terms the tabular list files under this code.
- Poisoning by thyroid hormones and substitutes NOS
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- mineralocorticoids and their antagonists T50.0-
- oxytocic hormones T48.0-
- parathyroid hormones and derivatives T50.9-
- toxic reaction to local anesthesia in pregnancy O29.3-
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- abuse and dependence of psychoactive substances F10-F19
- abuse of non-dependence-producing substances F55.-
- immunodeficiency due to drugs D84.821
- drug reaction and poisoning affecting newborn P00-P96
- pathological drug intoxication inebriation F10-F19
Code First
Underlying conditions that must be sequenced before this code.
- , for adverse effects, the nature of the adverse effect, such as:
- adverse effect NOS T88.7
- aspirin gastritis K29.-
- blood disorders D56-D76
- contact dermatitis L23-L25
- dermatitis due to substances taken internally L27.-
- nephropathy N14.0-N14.2
Use Additional Code
Supplementary codes the tabular list directs you to add.
- code(s) to specify:
- manifestations of poisoning
- underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
- underdosing of medication regimen (Z91.12-, Z91.13-)
Frequently Asked Questions (FAQ) & Clinical Guidance
Does T38.1X1A require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category T38.
What can't be coded together with T38.1X1A?
Per official ICD-10-CM Excludes1 instructions, T38.1X1A must not be reported together with: mineralocorticoids and their antagonists (T50.0-); oxytocic hormones (T48.0-); parathyroid hormones and derivatives (T50.9-); toxic reaction to local anesthesia in pregnancy (O29.3-).
Can T38.1X1A be reported alongside related conditions?
Per official ICD-10-CM Excludes2 instructions, T38.1X1A and the following are not considered part of each other and may both be reported when both conditions are present: abuse and dependence of psychoactive substances (F10-F19); abuse of non-dependence-producing substances (F55.-); immunodeficiency due to drugs (D84.821); drug reaction and poisoning affecting newborn (P00-P96).
Does T38.1X1A need to be sequenced after another code?
Yes. Code first: , for adverse effects, the nature of the adverse effect, such as:; adverse effect NOS (T88.7); aspirin gastritis (K29.-); blood disorders (D56-D76).
Is an additional code needed with T38.1X1A?
Use additional code(s) to specify: code(s) to specify:; manifestations of poisoning; underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9); underdosing of medication regimen (Z91.12-, Z91.13-).
Nearest Codes in This Family
Official ICD-10-CM classifications closest to T38.1X1A in its code family, with their registry titles.
- T38 — Poisoning by, adverse effect of and underdosing of hormones and their synthetic substitutes and antagonists, not elsewhere classified
- T38.0 — Poisoning by, adverse effect of and underdosing of glucocorticoids and synthetic analogues
- T38.0X — Poisoning by, adverse effect of and underdosing of glucocorticoids and synthetic analogues
- T38.0X1 — Poisoning by glucocorticoids and synthetic analogues, accidental (unintentional)
- T38.0X1A — Poisoning by glucocorticoids and synthetic analogues, accidental (unintentional), initial encounter
- T38.0X1D — Poisoning by glucocorticoids and synthetic analogues, accidental (unintentional), subsequent encounter
- T38.0X1S — Poisoning by glucocorticoids and synthetic analogues, accidental (unintentional), sequela
- T38.0X2 — Poisoning by glucocorticoids and synthetic analogues, intentional self-harm
- T38.0X2A — Poisoning by glucocorticoids and synthetic analogues, intentional self-harm, initial encounter
- T38.0X2D — Poisoning by glucocorticoids and synthetic analogues, intentional self-harm, subsequent encounter
View all 40 codes in the T38 family
Associated Substances (20)
Substances from the official ICD-10-CM Table of Drugs and Chemicals that map to this code.
- Cytomel
- Detrothyronine
- Dextrothyroxin
- Dextrothyroxine sodium
- Euthroid
- I-thyroxine sodium
- Letter
- Levoid
- Levothyroxine
- Liothyronine
- Liotrix
- Proloid
- Synthroid
- Thyroglobulin
- Thyroid (hormone)
- Thyrolar
- Thyroxine
- Tiratricol
- Titroid
- Triiodothyronine