Table 2.

Contingency table of CAT+ (reference standard) versus MHPA (MH diagnosis; index test)

	CAT+ (≥3 U RBC/60 min in 24 hours)	CAT− (<3 U RBC/60 min in 24 hours)
MHPA	97	45
No MHPA	41	764
Sensitivity=70.3% (95% CI 62.2% to 77.3%) Specificity=94.4% (95% CI 92.6% to 95.8%) PPV=68.3% (95% CI 60.3% to 75.4%) NPV=94.9% (95% CI 93.2% to 96.2%) FPR=45/(45+764)=5.56% FNR=41/(41+97)=29.71% LR=12.6

CAT, critical admission threshold; FNR, false negative rate; FPR, false positive rate; LR, likelihood ratio; MH, major hemorrhage; NPV, negative predictive value; PPV, positive predictive value; RBC, packed red blood cells.