TABLE 4.
Agreement and correlation between the field and standard coAg ELISA results classified into four categories of antigen levels for 1,355 known positive and negative stool samples collected in northern Peru, 2009a
| Field coAg ELISA | Standard coAg ELISA |
Total | |||
|---|---|---|---|---|---|
| PP < 7.5 | 7.5 ≤ PP < 14 | 14 ≤ PP < 40 | PP ≥ 40 | ||
| PP < 7.5 | 720 | 81 | 0 | 0 | 801 |
| 7.5 ≤ PP < 14 | 17 | 168 | 60 | 0 | 245 |
| 14 ≤ PP < 40 | 0 | 12 | 186 | 13 | 211 |
| PP ≥40 | 0 | 0 | 7 | 91 | 98 |
| Total | 737 | 261 | 253 | 104 | 1,355 |
| Pearson correlation (r) | 0.75 | 0.65 | 0.85 | 0.97 | 0.98 |
| Weighted kappa | 0.86 | ||||
a
Percentage of positivity (PP): [OD of the sample]/[OD of a known positive group (P1)] × 100.