Table 4.

Estimated probability of acute appendicitis according to the risk categories of Alvarado Score and positive C-reactive protein.

Alvarado score	Probability of AA (%)	CRP (mg/dl)	Probability of AA (%)
Low risk	8.8	≤0.5	5.2
		> 0.5	15.7
Intermediate risk	27.6	≤0.5	15.2
		> 0.5	37.7
High risk	58.2	≤0.5	36.9
		> 0.5	66.4
TOTAL	35.0	≤0.5	16.4
		> 0.5	49.7

AA: acute appendicitis; CRP: C-reactive protein