4AT Rapid Delirium Screening Test

A brief, validated screening tool for delirium detection that incorporates cognitive testing and assessment of acute change. Designed for routine clinical practice.

Warnings:
  • 4AT is a screening tool, not a diagnostic instrument
  • A high AMT4 score can indicate general cognitive impairment but does not rule out mild cognitive impairment
  • Item 4 (acute change) requires information from GP letters, family, or nursing staff
  • If insufficient information for Item 4, leave blank and score 0-8; still interpret cautiously
  • Sensitivity ~72%, specificity ~84% for DSM-5 delirium in real-world settings
  • Formal training recommended, especially for scoring Items 1 and 4
  • Recommended in NICE guidelines for delirium detection
Note: Takes approximately 2 minutes to complete. AMT4 alone scores 0-2; combined with other items, maximum score is 12. The 4AT does not require baseline cognitive data. If no informant available for acute change, can still proceed with first 3 items.
Observe patient. If asleep, attempt to wake with speech or gentle touch. Ask patient to state name and address.
Ask patient: Age, Date of birth, Place (hospital/building), Current year. Score 0, 1, or 2 errors.
Ask: 'Please tell me the months of the year in backwards order, starting at December.' One prompt permitted.
Evidence of significant change in alertness, cognition, or other mental function over last 2 weeks, still evident in last 24 hours. Requires collateral history.