T65.0X1D Toxic effect of cyanides, accidental (unintentional), subsequent encounter

ICD-10-CM T65.0X1D: Toxic effect of cyanides, accidental (unintentional), subsequent encounter

ICD-10-CM code T65.0X1D represents the toxic effect of cyanides resulting from an accidental or unintentional exposure, specifically for a subsequent encounter. It is classified under the semantic type of Injury or Poisoning. This code is used for patient care encounters occurring during the healing or recovery phase after the active treatment for the exposure has ended. 1 3 6

Plain-language overview

Code T65.0X1D identifies a diagnosis of toxic effect of cyanides caused by accidental or unintentional exposure, specifically documenting a subsequent medical encounter for the patient. 1

What this code represents

The terminology record for T65.0X1D assigns a semantic type of Injury or Poisoning and lists its parent concept as T65.0X1, which denotes the accidental toxic effect of cyanides. 1

In ICD-10-CM, toxic effects of nonmedicinal substances are assigned diagnosis codes in the T51 to T65 range, and the intent of the injury is captured directly within a character of the code. 3

Coding details

The seventh character D in injury diagnosis codes identifies a subsequent encounter, which applies to routine care during the healing or recovery phase after active treatment has ended. 3

Documentation considerations

Clinical documentation for T65.0X1D establishes the toxic effect of cyanides, the accidental or unintentional nature of the exposure, and that the current visit is a subsequent encounter. 1 3

Coverage and utilization context

The code T65.0X1D appears in a Medicare billing and coding article for head computed tomography services, illustrating its use in administrative billing contexts. 5

What the sources add

While the National Cancer Institute terminology record provides the official code definition and hierarchy, the Centers for Disease Control and Prevention reports explain the structural rules for seventh character encounters and intent. 1 3

Historical public health surveillance utilized older ICD-9-CM codes, such as 989.0 for the toxic effect of hydrocyanic acid and cyanides, to track unintentional and accidental pesticide-related illnesses. 2

Sources

1. ICD-10-CM T65.0X1D terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Public Health Surveillance for the Prevention of Pesticide- ... — stacks.cdc.gov; accessed 2026-07-27.
3. National Health Statistics Reports — cdc.gov; accessed 2026-07-27.
4. Article - Billing and Coding: Oximetry Services (A57205) — cms.gov; accessed 2026-07-27.
5. Article - Billing and Coding: CT of the Head (A56612) — cms.gov; accessed 2026-07-27.
6. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.