Table 3

Test performance characteristics of specific HbA1c thresholds for detecting pre-diabetes and diabetes according to OGTT

HbA1c threshold	Pre-diabetes (IFG+IGT)			T2DM
HbA1c threshold	Sensitivity	1-specificity	Sensitivity+specificity	Sensitivity	1-specificity	Sensitivity+specificity
2.7	1.000	1.000	1.000	1.000	1.000	1.000
3.8	1.000	0.998	1.002	1.000	0.998	1.002
4.0	1.000	0.996	1.004	1.000	0.996	1.004
4.1	1.000	0.994	1.006	1.000	0.995	1.005
4.3	1.000	0.992	1.008	1.000	0.993	1.007
4.5	1.000	0.990	1.010	1.000	0.991	1.009
4.7	0.982	0.986	0.997	1.000	0.986	1.014
4.8	0.982	0.972	1.011	1.000	0.973	1.027
4.9	0.982	0.950	1.033	1.000	0.953	1.047
5.0	0.965	0.911	1.054	1.000	0.917	1.083
5.1	0.895	0.853	1.042	1.000	0.857	1.143
5.2	0.877	0.764	1.113	1.000	0.776	1.224
5.3	0.825	0.615	1.210	1.000	0.635	1.365
5.4	0.702	0.452	1.250	1.000	0.476	1.524
5.5	0.614	0.315	1.300	1.000	0.344	1.656
5.6	0.491	0.200	1.292	0.900	0.228	1.672
5.7	0.316	0.115	1.201	0.900	0.136	1.764
5.8	0.175	0.058	1.117	0.900	0.071	1.829
5.9	0.123	0.026	1.097	0.900	0.036	1.864
6.0	0.070	0.014	1.056	0.900	0.020	1.880
6.1	0.070	0.006	1.064	0.900	0.013	1.887
6.2	0.070	0.004	1.066	0.800	0.011	1.789
6.3	0.053	0.004	1.049	0.800	0.009	1.791
6.4	0.035	0.002	1.033	0.800	0.005	1.795
6.5	0.035	0.000	1.035	0.700	0.004	1.696
6.8				0.700	0.000	1.700
7.1				0.600	0.000	1.600
7.4				0.500	0.000	1.500
8.4				0.400	0.000	1.400
9.5				0.300	0.000	1.300
10.4				0.200	0.000	1.200
12.5				0.100	0.000	1.100
14.8				0.000	0.000	1.000

HbA1c, haemoglobin A1c; IFG, impaired fasting glucose; IGT, impaired glucose tolerance; OGTT, oral glucose tolerance test; T2DM, type 2 diabetes.