TABLE 4.
Association between cagA genotype and detection of anti-CagA antibodies by various assays
| Assay and result | No. with genotypea
|
Kappa value | Sensitivity (%) (95% CI) | Specificity (%) (95% CI) | PPV (%) (95% CI)c | NPV (%) (95% CI)d | |
|---|---|---|---|---|---|---|---|
| cagA negative | cagA positive | ||||||
| Helicoblot 2.0 | 0.557 (0.339–0.776) | 71.4 (52.9–84.7) | 84.6 (66.5–93.8) | 83.3 (64.1–93.3) | 73.3 (55.6–85.8) | ||
| Negative | 22 | 8 | |||||
| Positive | 4 | 20 | |||||
| Dubious | 7 | 0 | |||||
| Helicoblot 2.1 | 0.332 (0.079–0.586) | 78.6 (60.4–89.8) | 54.2 (35.1–72.1) | 66.6 (49.6–80.2) | 68.4 (46.0–84.6) | ||
| Negative | 13 | 6 | |||||
| Positive | 11 | 22 | |||||
| Dubious | 9 | 0 | |||||
| Pyloriset | 0.632 (0.438–0.826) | 71.4 (52.9–84.7) | 90.9 (76.4–96.8) | 87.0 (67.9–95.5) | 79.0 (63.8–88.9) | ||
| Negative | 30 | 8 | |||||
| Positive | 3 | 20 | |||||
| DDL | 0.736 (0.565–0.906) | 85.7 (68.5–99.3) | 87.9 (72.7–95.2) | 85.7 (68.5–94.3) | 87.9 (72.7–95.2) | ||
| Negative | 29 | 4 | |||||
| Positive | 4 | 24 | |||||
| Vanderbilt | 0.696 (0.521–0.870) | 67.9 (49.3–82.1) | 100 (89.6–100) | 100 (83.2–100) | 78.6 (64.1–88.3) | ||
| Negative | 33 | 9 | |||||
| Positive | 0 | 19 | |||||
a
Including patients whose specimens contained multiple vacA genotypes.
b
CI, confidence interval.
c
PPV, positive predictive value.
d
NPV, negative predictive value.