Left Without Being Seen is a healthcare term often used by emergency department

Emergency department

An emergency department , also known as accident & emergency , emergency room , emergency ward , or casualty department is a medical treatment facility specialising in acute care of patients who present without prior appointment, either by their own means or by ambulance...

s (ED) to designate a patient encounter that ended with the patient leaving the healthcare setting before the patient could be seen by a certified physician

Physician

A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

. Often the inclusion of this phrase in a medical record

Medical record

The terms medical record, health record, and medical chart are used somewhat interchangeably to describe the systematic documentation of a single patient's medical history and care across time within one particular health care provider's jurisdiction....

 is the result of ED overcrowding (i.e. the patient could no longer wait in the ED to be seen by a physician, so they left without alerting a healthcare professional). Typically, those patients who leave an emergency department without being seen are not at an increased risk of death, and often do not require inpatient hospital admission.