Table 2.
Diagnostic accuracy of urine glucose test strip, capillary fasting glucose and HbA1c determined by comparison with the composite reference standard (n=1289)*
| Urine glucose test strip positive | cFBG≥126 mg/dL | HbA1c>6.5% | |
| True positive (n) | 33 | 173 | 176 |
| False positive (n) | 7 | 34 | 16 |
| False negative (n) | 201 | 61 | 58 |
| True negative (n) | 1048 | 1021 | 1039 |
| True diabetes prevalence† (95% CI) | 18%, 234/1289 (16 to 20.4) | ||
| Sensitivity (95% CI) | 14.1 (9.90 to 19.2) | 73.9 (67.8 to 79.4) | 75.2 (69.2 to 80.6) |
| Specificity (95% CI) | 99.3 (98.6 to 99.7) | 96.8 (95.5 to 97.8) | 98.5 (97.5 to 99.1) |
| Positive PV (95% CI) | 82.5 (67.2 to 92.7) | 83.6 (77.8 to 88.3) | 91.7 (86.8 to 95.2) |
| Negative PV (95% CI) | 83.9 (81.7 to 85.9) | 94.4 (92.8 to 95.7) | 94.7 (93.2 to 96.0) |
| Positive LR (95% CI) | 21.3 (9.50 to 47.5) | 22.9 (16.3 to 32.2) | 49.6 (30.3 to 81.1) |
| Negative LR (95% CI) | 0.90 (0.80 to 0.90) | 0.30 (0.20 to 0.30) | 0.30 (0.20 to 0.30) |
*Excludes individuals taking diabetes treatment that day (n=6), did not fast before OGTT as instructed (n=5) or did not complete the OGTT (n=16).
†Composite reference standard: OGTT ≥200 mg/dL or cFBG ≥200 mg/dL. Seventy patients with cFBG≥200 were not tested by OGTT.
cFBG, capillary fasting blood glucose; LR, likelihood ratio; OGTT, oral glucose tolerance test; PV, predictive value.