TABLE 5.
Statistical performance of serology assays using cutoff values recommended by the manufacturer or determined by logistic regression analysisa
| Parameter | Value(s) for indicated assay |
||||
|---|---|---|---|---|---|
| EMA (titer) | tTG-IgA Celikey (U/ml) | tTG-IgA Immulite 2000 (U/ml) | DGP IgA+IgG screen (U) | tTG-IgG Celikey (U/ml) | |
| Cutoff points recommended by the manufacturer | |||||
| Cutoff value | <1/5 (−), ≥1/5 (+) | <5 (−), 5-8 (BL), >8 (+) | <4 (−), ≥4 (+) | <20 (−), 20-30 (w+), > 30 (s+) | <7 (−), 7-10 (BL), >10 (+) |
| Sensitivity (%) | 95.3 | 94.1 | 92.9 | 95.3 | 67.7 |
| Specificity (%) | 74.2 | 87.1 | 74.2 | 64.5 | 93.5 |
| PPV (%) | 91.0 | 95.2 | 90.8 | 83.3 | 96.5 |
| NPV (%) | 85.2 | 84.4 | 79.3 | 88 | 49.2 |
| Test efficiency (%) | 89.6 | 91.4 | 87.9 | 87 | 72.4 |
| Cutoff points determined by logic regression analysis | |||||
| Cutoff value | <1/10 (−), ≥1/10 (+) | <7 (−), ≥7 (+) | <10 (−), ≥10 (+) | <34 (−), ≥34 (+) | <3.6 (−), ≥3.6 (+) |
| Sensitivity (%) | 90.6 | 90.6 | 90.6 | 89.4 | 81.2 |
| Specificity (%) | 96.8 | 96.8 | 87.1 | 83.9 | 83.9 |
| PPV (%) | 98.7 | 98.7 | 95.1 | 93.8 | 93.2 |
| NPV (%) | 78.9 | 78.9 | 77.1 | 74.3 | 61.9 |
| Test efficiency (%) | 92.2 | 92.2 | 89.7 | 87.9 | 81.9 |
a
−, negative; +, positive; w+, weak positive; s+, strong positive; BL, borderline. Borderline and weak-positive results were considered positive for calculating sensitivity, specificity, PPV, NPV, and test efficiency.