Table 1. Diagnostic accuracy measuring of blood parameters in diagnosing β-thalassemia carrier status (n=418).

PPV: Positive predictive value, NPV: Negative predictive

Parameter	Cut-off	Sensitivity	Specificity	Accuracy	PPV	NPV	Youden’s index
MCV	< 80 fL	71.4	71.0	71.1	21.6	95.7	42.4
MCH	< 1.67 fmol	69.0	69.4	69.3	20.1	95.3	38.4
MCHC	< 20.7 mmol/L	66.7	63.6	63.9	17.0	94.5	30.3
RDW	> 13.95%	66.7	65.4	65.6	17.7	94.6	32.1
RBC	> 4.995	73.8	69.9	70.3	21.5	96.0	43.7