CAM Derivatives

CAM has limitations in the Emergency Department

Performing a 5-minute delirium assessment may be too long in the busy ED environment, where emergency physicians and nurses may face immense time constraints. The CAM also relies on the rater’s clinical judgment; this assessment is operator dependent and its diagnostic accuracy is dependent on the rater’s clinical experience and level of training.

One way to reduce both the amount of time it takes and operator dependency is to incorporate objective cognitive testing with prespecified cutoffs. The advantage of this approach is that it increases the delirium assessment’s brevity, ease of use, and allows it to be reliably used by raters with minimal training. However, this usually comes at the expense of diagnostic accuracy.

With these factors in mind, several delirium assessments have been developed based upon the CAM algorithm:

  1. brief Confusion Assessment Method (bCAM)
  2. Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)
  3. 3-Minute Diagnostic Interview for CAM (3D-CAM)
3D-CAM, 3-Minute Diagnostic Interview for Confusion Assessment Method
bCAM, brief CAM
CAM, Confusion Assessment Method
CAM-ICU, CAM for the Intensive Care Unit
RASS, Richmond Agitation Sedation Scale


The bCAM, CAM-ICU, and 3D-CAM incorporate brief cognitive testing with prespecified cutoffs to determine inattention and disorganized thinking. For example, the bCAM asks the patient to recite the months backwards from December to July to determine Feature 2 (inattention); a patient who makes 2 or more errors in this task is considered to be Feature 2–positive or inattentive.


CAM, Confusion Assessment Method

ED, emergency department