Table 2. 2×2 table summary statistics for the combined MAS/CRP predictive outcomes.

MAS: modified Alvarado score; PPV: positive predictive value; NPV: negative predictive value; CRP: C-reactive protein; TP: true positive; FP: false positive; FN: false negative; TN: true negative

		Patients with acute appendicitis confirmed on histopathology
		Positive histopathology	Negative histopathology
CRP/MAS	Positive CRP/MAS	178 (TP)	4 (FP)	PPV = 97.8%
	Negative CRP/MAS	17 (FN)	31 (TN)	NPV = 64.5%
		Sensitivity = 91.2%	Specificity = 88.5%	Accuracy (TP+TN) = 90.86%