Table 1.

eCATs: Elements and examples

Element	Example 1			Example 2
Short title	Palpation for abdominal aortic aneurysm (AAA)			Ferritin for iron deficiency
Bottom line	1. Abnormal aortic contour on palpation can raise probability of AAA greatly.2. Normal palpation cannot accurately rule out AAA.			1. In suspected iron deficiency, serum ferritin is accurate and precise, dominating other tests, even with inflammatory disease.
	2. Normal palpation cannot accurately rule out AAA.

Results	Size of aneurysm	+LR	−LR	Ferritin measurement (ng/ml)	LR
	>3 cm	12.0	0.72	<15	51.85
	>4 cm	15.6	0.51	>15 to <25	8.83
				>25 to <35	2.54
				>35 to <45	1.83
				>45 to <100	0.54
				>100	0.08
Source	Systematic review of studies of examination for AAA, involving 2955 patients			Systematic review of studies with marrow iron as standard, involving 2579 patients
Citation	JAMA 1999;281:77–82.			J Gen Intern Med 1992;7:145–53.
eCAT date	9 January 1999			10 August 1998