T50.995A Adverse effect of other drugs, medicaments and biological substances, initial encounter

ICD-10-CM T50.995A: Adverse Effect of Other Drugs, Medicaments and Biological Substances, Initial Encounter

ICD-10-CM code T50.995A identifies an adverse effect of other drugs, medicaments, and biological substances during an initial encounter. The concept is active for 2026 and falls under the broader parent code T50.995. It is assigned a semantic type of Injury or Poisoning and appears in payer coding articles. 1 4

Plain-language overview

Medicines can cause unwanted reactions, such as drug interactions, side effects, and allergies, while adverse drug events are defined as unintended and harmful effects resulting from medication use. 2 6

What this code represents

The official label for T50.995A is adverse effect of other drugs, medicaments and biological substances, initial encounter, and it carries the semantic type of Injury or Poisoning. 1

Code T50.995A is an active 2026 ICD-10-CM terminology concept that has narrower concepts and belongs to the parent concept T50.995 for adverse effects. 1

Coding details

Code T50.995A is listed alongside T50.995S, which represents an adverse effect of other drugs, medicaments and biological substances within the same terminology record. 5

Documentation considerations

Health researchers note that adverse drug events are underreported in administrative data, and the effect of coding quality on identifying these events is poorly understood. 2

Coverage and utilization context

Code T50.995A appears in a Centers for Medicare and Medicaid Services article detailing added ICD-10-CM codes for administrative billing and coding purposes. 4

What the sources add

While terminology records define the code structure and label, research articles emphasize that adverse drug events are a growing public health concern associated with increased health services utilization. 1 2

A systematic review highlights that adverse drug reactions occur when drugs are used in therapeutic doses, whereas the terminology record assigns the broader Injury or Poisoning semantic type. 1 2

Questions to verify

The supplied sources do not establish the specific documentation elements required to support the clinical use of T50.995A for a patient's initial encounter. 1 4

Sources

1. ICD-10-CM T50.995A terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. ICD-10 codes used to identify adverse drug events in administrative data: a systematic review — pmc.ncbi.nlm.nih.gov; accessed 2026-07-27.
3. Article - Billing and Coding: Paclitaxel (e.g., Taxol®/Abraxane ™) (A52450) — cms.gov; accessed 2026-07-27.
4. Article - Billing and Coding: Allergy Testing (A56558) — cms.gov; accessed 2026-07-27.
5. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
6. T50.995A — Adverse effect of other drugs, medicaments and biological substances, initial encounter | ICD-10 Code · Eleplan — eleplan.com; accessed 2026-07-27.