T56.891D Toxic effect of other metals, accidental (unintentional), subsequent encounter

ICD-10-CM Diagnosis Code T56.891D: Toxic effect of other metals, accidental (unintentional), subsequent encounter

ICD-10-CM code T56.891D designates the subsequent encounter for an accidental toxic effect of other metals. Terminology records classify this concept as an injury or poisoning. The code appears in Medicare billing and coding articles as a diagnosis supporting medical necessity for heavy metal testing. 1 4

Plain-language overview

The official label for T56.891D is toxic effect of other metals, accidental (unintentional), subsequent encounter, and the concept's semantic type is injury or poisoning. 1

What this code represents

Code T56.891D is an active terminology concept that has a parent concept of T56.891, representing the toxic effect of other metals from accidental or unintentional causes. 1

The terminology record for T56.891D includes an abbreviation noting it is the subsequent encounter for the accidental toxic effect of other metals, and the record indicates it has narrower concepts. 1

Coding details

The official terminology record for T56.891D lists T56.891 as its parent concept, and a separate terminology explorer site confirms the exact code and official label for T56.891D. 1 3

Documentation considerations

The terminology record establishes that T56.891D represents a subsequent encounter for the toxic effect of other metals, while a billing article mentions the initial encounter code T56.891A for toxic effects of other metals. 1 2

Coverage and utilization context

A Medicare billing and coding article for heavy metal testing lists T56.891D as an ICD-10-CM code that supports medical necessity under the section for codes that support medical necessity. 4

The CMS heavy metal testing article includes T56.891D among codes supporting medical necessity, while the terminology record independently defines the code's official label and semantic type. 1 4

What the sources add

The National Cancer Institute terminology record provides the official code status and hierarchy, whereas the CMS article provides operational context by listing the code for medical necessity support in heavy metal testing. 1 4

Questions to verify

The supplied sources do not identify which specific metals are classified as other metals under code T56.891D, nor do they detail the clinical symptoms or documentation elements required for this diagnosis. 1 4

Sources

1. ICD-10-CM T56.891D terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Article - Billing and Coding: Heavy Metal Testing (A56767) — cms.gov; accessed 2026-07-27.
3. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
4. Article - Billing and Coding: Heavy Metal Testing (A56767) — cms.gov; accessed 2026-07-27.