Table 3

Diagnostic usefulness and predictive values at different haemoglobin (Hb) values using best scale readings where discrepancies occurred (n = 548)

Scale readings
Reference Hb (g/dl)<66 to <88 to <1010 to <1212 or more
FN, false negative; FP, false positive; LR, likelihood ratio; NPV, negative predictive value; PPV, positive predictive value; TN, true negative; TP, true positive.
<6342000
6 to <8227500
8 to <10038783
10 to <120047436
12 or more0009254
TP34278774254
FP2591739
FN2714409
TN509508438396245
Sensitivity (%)94.479.486.064.996.6
Specificity (%)99.699.098.095.986.3
PPV (%)94.484.390.681.386.7
NPV (%)99.698.696.990.896.5
LR0.940.780.840.610.83