T42.0X6D Underdosing of hydantoin derivatives, subsequent encounter

ICD-10-CM T42.0X6D: Underdosing of hydantoin derivatives, subsequent encounter

ICD-10-CM code T42.0X6D is an active terminology concept representing the underdosing of hydantoin derivatives during a subsequent encounter. The code is classified under the parent concept of underdosing of hydantoin derivatives and carries the semantic type of injury or poisoning. It also appears in official billing and coding guidance for controlled substance monitoring. 1 2 5

Plain-language overview

Code T42.0X6D is an active ICD-10-CM terminology concept used to classify an instance of underdosing of hydantoin derivatives during a subsequent patient encounter. 1

What this code represents

The official preferred name for T42.0X6D is underdosing of hydantoin derivatives, subsequent encounter, and the concept is assigned the semantic type of injury or poisoning. 1 5

Within the ICD-10-CM hierarchy, T42.0X6D is explicitly listed as a narrower concept of the parent code T42.0X6, which is titled underdosing of hydantoin derivatives. 1

Coding details

The terminology record for T42.0X6D indicates that this active code has narrower concepts within the ICD-10-CM version 2026 terminology system, but does not detail them. 1

Documentation considerations

The official terminology record and vocabulary services identify the full label for T42.0X6D as underdosing of hydantoin derivatives, subsequent encounter, but do not detail specific documentation elements. 1 3

Coverage and utilization context

Code T42.0X6D appears in official billing and coding guidance for a Local Coverage Determination concerning controlled substance monitoring and drugs of abuse testing. 2

What the sources add

While one terminology source defines the hierarchical structure of T42.0X6D, a separate billing article provides operational context by listing the code within Medicare coverage guidance for substance monitoring. 1 2

Multiple official vocabulary services confirm the preferred name and semantic type for T42.0X6D, while a separate billing article references hydantoin derivatives in the context of accidental poisoning. 3 4 5

Sources

1. ICD-10-CM T42.0X6D terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Article - Billing and Coding: Controlled Substance Monitoring and Drugs of Abuse Testing (A56645) — cms.gov; accessed 2026-07-27.
3. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
4. Article - Billing and Coding: Controlled Substance Monitoring and Drugs of Abuse Testing (A57077) — cms.gov; accessed 2026-07-27.
5. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.