FAST is an acronym used as a mnemonic

Mnemonic

A mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...

 to help detect and enhance responsiveness to stroke

Stroke

A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

 victim needs. The acronym stands for Facial weakness, Arm weakness, Speech difficulty, and Time to act.

Facial weakness judges whether the person can smile without their mouth or eyes dropping. Arm weakness is whether the person can hold up both arms successfully. Speech difficulty is about whether the person can speak clearly and understand speech. Time represents the need to get to a hospital (e.g., calling for help) immediately.

History

The FAST (aka the Face Arm Speech Test, amongst medical professionals) was developed in the UK in 1998 by a group of stroke physicians, ambulance personnel, and an emergency room physician and was designed to be an integral part of a training package for ambulance staff. The FAST was created to expedite administration of intravenous tissue plasminogen activator to patients within 3 hours of acute stroke symptom onset. The instruments at this time with most evidence of validity were the Cincinnati Prehospital Stroke Scale (CPSS) and the Los Angeles Prehospital Stroke Screen (LAPSS).