U00-U49: Provisional assignment of new diseases of uncertain etiology or emergency use

U27: Emergency use of U27

The U27 code in the ICD-10 WHO 2016 classification refers to a group of conditions that are seeing emergency use. These are usually new, emerging, or rare diseases that lack a defined classification yet require immediate attention due to their potential risk to public health. They may be infectious or non-infectious in nature, but typically present with sudden onset of symptoms which could be severe or life-threatening. The conditions within this group may be caused by a variety of factors including bacteria, viruses, environmental exposures, genetic mutations, or unknown causes. Symptoms vary widely depending on the particular disease, but could include significant discomfort, system-dysfunction, or deterioration of health. The diseases under this group typically require emergent medical attention because of the potential for rapid disease progression and severe outcomes.