Value Sensitivity % Specificity % Likelihood Ratio Acute         WCC (cells/mm3) >14.05 48.9 76.27 2.06 CRP (mg/l) >7.5 69.73 50 1.39 Complicated         WCC (cells/mm3) >13.95 59.57 61.56 2.34 CRP (mg/l) >7 91.67 50 1.83

Table 3: Receiver-operator characteristic (ROC) curve derived figures showing sensitivity, specificity and likelihood ratio for both acute and complicated patient groups with respect to the pre-operatively blood test. Normal Reference ranges were used as an arbitrary cut-off point holds no clinical value unless widely accepted by clinicians.