2025 ICD-10-CM code X99.1

Assault by knife.

Always use X99.1 as a secondary code to a code from another chapter describing the nature of the injury. Never use it as a primary diagnosis.Ensure that the documentation clearly supports the use of this code, including evidence that the injury was the result of an assault with a knife.

The medical necessity for using X99.1 is to accurately reflect the external cause of the patient's injuries. This information is crucial for statistical tracking, public health reporting, and potential legal investigations. It provides a more complete picture of the patient's condition and helps to ensure appropriate resource allocation and intervention strategies.

Clinicians should document the specific details of the assault, the type of knife used, and the resulting injuries.It's essential to use this code as a secondary code to a code from another chapter, such as Chapter 19 (Injury, poisoning, and certain other consequences of external causes), which describes the nature of the injury itself.

In simple words: This code represents an assault where the victim was injured with a knife.

Assault by knife. This code indicates an injury inflicted by another person with the intent to injure or kill, specifically using a knife.

Example 1: A patient presents to the emergency department with a stab wound to the abdomen following an assault with a kitchen knife. The primary diagnosis would be the specific injury code (e.g., penetrating wound of the abdomen), and X99.1 would be used as a secondary code to indicate the cause of the injury., A patient is found unconscious with multiple lacerations consistent with knife wounds. While the perpetrator is unknown, the injuries suggest an assault. The appropriate injury codes would be assigned as primary diagnoses, and X99.1 would be used as a secondary code., A patient reports being threatened by an assailant with a knife but manages to escape without physical injury. In this case, a code from Chapter 21 (Factors influencing health status and contact with health services (Z00-Z99)) relating to the threat or encounter would be primary and X99.1 would not be applicable as there was no physical assault with a knife.

Documentation should include a detailed description of the assault, including the circumstances surrounding the event, the type of weapon used (specify the type of knife if known), and the location and severity of the injuries sustained.Any witness statements or police reports can also be valuable supporting documentation.

** It's crucial to distinguish between assault and other forms of violence, such as legal intervention (Y35.-), operations of war (Y36.-), or terrorism (Y38.-), as these have separate codes.This distinction helps in accurately classifying the event and gathering relevant data for statistical analysis and public health purposes.

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