Table 2. Diagnostic performance of glycated hemoglobin (HbA1c) test for detecting gestational diabetes mellitus (GDM) at different HbA1c threshold.

HbA1c-thresholds, % [mmol/mol]	Sensitivity, %	Specificity, %	Positive predictive value (PPV), %	Negative predictive value (NPV), %	Positive likelihood ratio (LR+)	Negative likelihood ratio (LR−)	F1 value	Youden index
4.5 [26]	94.1	12.9	19.6	90.7	1.081	0.455	0.325	0.071
4.6 [27]	90.6	20.7	20.5	90.6	1.141	0.457	0.334	0.112
4.7 [28]	85.2	29.9	21.5	89.9	1.215	0.496	0.344	0.151
4.8 [29]	79.2	41.4	23.4	89.8	1.353	0.502	0.361	0.206
4.9 [30]	70.6	53.5	25.5	89.0	1.519	0.550	0.375	0.241
5.0 [31]	60.1	65.3	28.1	87.9	1.733	0.610	0.383	0.254
5.1 [32]	47.8	74.9	30.1	86.4	1.910	0.696	0.370	0.228
5.2 [33]	37.3	83.6	33.9	85.5	2.271	0.750	0.355	0.209
5.3 [34]	28.2	89.3	37.4	84.6	2.643	0.804	0.321	0.175
5.4 [35]	19.7	93.3	39.7	837	2.916	0.862	0.263	0.129
5.5 [37]	13.0	95.8	41.4	830	3.130	0.908	0.198	0.089