4AT Calculator for Delirium Screening

The 4AT is a widely used, rapid screening tool for delirium and cognitive impairment. It takes around two minutes, needs no special training, and scores four items — alertness, the AMT4 cognitive screen, attention (months of the year backwards) and evidence of acute change or fluctuating course — to give a total out of 12.

A 4AT score of 4 or more suggests possible delirium with or without cognitive impairment. A score of 1–3 suggests possible cognitive impairment. A score of 0 makes delirium or significant cognitive impairment unlikely, though it does not entirely exclude it. The 4AT is a screening tool and should always be combined with clinical judgement.

The four items are: (1) Alertness; (2) AMT4 — age, date of birth, place and current year; (3) Attention — naming the months of the year in reverse; and (4) Acute change or fluctuating course in mental status. SnapMedic walks through each item and totals the score automatically.

Delirium is common, frequently missed, and associated with poorer outcomes — particularly in older patients. A quick, structured 4AT screen on scene or at handover helps flag possible delirium early, supports safer decisions about conveyance and capacity, and gives the receiving team a clear baseline.

Yes. The 4AT calculator is included free in SnapMedic with no in-app purchase, and works fully offline — all scoring runs locally on your device, so it is reliable anywhere with no mobile signal.