Table 2.
Test performance characteristics of an HbA1c threshold of 6.5% for detecting diabetes according to fasting plasma glucose (FPG) or 2-hour plasma glucose (2-hr PG), and HbA1c thresholds of 6.0% and 5.7% for detecting prediabetes according to FPG or 2-hr PG in adolescents and adults.
| Criterion | Age Group | Total n | Cases n | Sensitivity (95% CI) |
Specificity (95% CI) |
PPV | NPV |
|---|---|---|---|---|---|---|---|
| Diabetes (HbA1c 6.5%) | |||||||
| Fasting plasma glucose |
Adolescents | 1156 | 4 | 75.0% (30.1–95.4) |
99.9% (99.5–100.0) |
75.0% | 99.9% |
| Adults | 6751 | 240 | 53.8% (47.4–60.0) |
99.5% (99.3–99.6) |
79.1% | 98.3% | |
| 2-hour plasma glucose |
Adolescents | 267 | 0 | - | - | - | - |
| Adults | 1476 | 91 | 30.8% (22.2–40.9) |
99.6% (99.2–99.9) |
84.8% | 95.6% | |
| Prediabetes (HbA1c 6.0%) | |||||||
| Fasting plasma glucose |
Adolescents | 1156 | 181 | 1.1% (0.3–3.9) |
99.4% (98.7–99.7) |
25.0% | 84.4% |
| Adults | 6751 | 2100 | 11.4% (10.1–12.9) |
94.7% (94.0–95.3) |
49.3% | 70.3% | |
| 2-hour plasma glucose |
Adolescents | 267 | 20 | 0.0% (0.0–16.1) |
99.6% (97.7–99.9) |
0.0% | 92.5% |
| Adults | 1476 | 227 | 13.2% (9.4–18.2) |
93.0% (91.4–94.3) |
25.4% | 85.5% | |
| Prediabetes (HbA1c 5.7%) | |||||||
| Fasting plasma glucose |
Adolescents | 1156 | 181 | 5.0% (2.6–9.2) |
98.3% (97.2–98.9) |
34.6% | 84.8% |
| Adults | 6751 | 2100 | 23.1% (21.3–25.0) |
91.1% (90.3–91.9) |
54.0% | 72.4% | |
| 2-hour plasma glucose |
Adolescents | 267 | 20 | 0.0% (0.0–16.1) |
97.6% (94.8–98.9) |
0.0% | 92.3% |
| Adults | 1476 | 227 | 26.9% (21.5–33.0) |
87.2% (85.2–88.9) |
27.6% | 86.8% | |