Wong et al performed a meta-analysis that included 12 studies that enrolled 1,036 patients. Based upon the likelihood ratios, a positive CAM strongly increases the odds of delirium, and a negative CAM moderately to strongly decreases the likelihood of delirium. There is limited validation for older ED patients; Fabbri et al observed that the CAM was 94% and 96% specific when performed by geriatricians.
Because the CAM relies on the rater’s clinical judgment to determine Features 2 (inattention) and 3 (disorganized thinking), it is operator dependent.
The CAM’s diagnostic accuracy may be poorer in nonphysicians and those with limited training. Therefore, the CAM requires extensive training to perform accurately and reliably.
However, of all the delirium assessments reviewed, the CAM has the highest ceiling with regard to diagnostic accuracy, especially if performed by an experienced rater.
Additional details about the CAM, including the instruction manual, can be seen at www.hospitalelderlifeprogram.org.
CAM, Confusion Assessment Method
ED, emergency department