S70.321A Blister (nonthermal), right thigh, initial encounter

ICD-10-CM S70.321A: Blister (nonthermal), right thigh, initial encounter

ICD-10-CM code S70.321A identifies a nonthermal blister located on the right thigh during an initial encounter. The concept is classified with the semantic type of injury or poisoning. This reference summarizes terminology records and coverage articles that mention the code, without providing personalized medical advice or implying guaranteed coverage. 1 5

Plain-language overview

Code S70.321A is an active ICD-10-CM terminology concept representing a nonthermal blister on the right thigh for an initial encounter, and it carries the semantic type of Injury or Poisoning. 1

What this code represents

The official preferred name for S70.321A is Blister (nonthermal), right thigh, initial encounter, and the concept carries the semantic type of Injury or Poisoning. 1 5

Coding details

In the ICD-10-CM hierarchy, S70.321A is a narrower concept descending from the parent code S70.321, which denotes a nonthermal blister of the right thigh. 1

The terminology record for S70.321A indicates an active status for the 2026 version of ICD-10-CM and confirms the concept has narrower child concepts within the terminology. 1

Documentation considerations

The code label explicitly specifies laterality as the right thigh and the encounter character as an initial encounter, distinguishing it from the parent concept without the encounter designation. 1

Coverage and utilization context

A Medicare billing and coding article for tetanus immunization administration lists S70.321A among codes documented in CGS coverage and coding guidelines for the administration of tetanus toxoids. 2

What the sources add

Two official terminology sources provide identical preferred names and semantic types for S70.321A, while a separate CMS coverage article places the code within a vaccine billing context. 1 5 2

The CMS tetanus immunization article mentions S70.321A in the context of CGS coverage and coding guidelines, whereas the NCI terminology record establishes the code's hierarchical parent and active status. 2 1

Questions to verify

Whether S70.321A appears in the tetanus immunization article as a covered diagnosis for vaccine administration or merely as a listed reference code is not established by the supplied excerpts. 2

Sources

1. ICD-10-CM S70.321A terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Article - Billing and Coding: Tetanus Immunization (A52438) — cms.gov; accessed 2026-07-27.
3. Article - Billing and Coding: Medicare Preventive Coverage for Certain Vaccines (A54767) — cms.gov; accessed 2026-07-27.
4. National Health Statistics Reports — cdc.gov; accessed 2026-07-27.
5. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.