Table 4.
Using the current antibody titers with different cutoff values to predict first PA+ in young children with CF from diagnosis to age 6 years when 44/69 (64%) of the patients have their first PA positive culture.
| Cell lysate | Exotoxin A | Elastase | |
|---|---|---|---|
| Using minimum cutoffs (6 (1:64) for lysate, 4 (1:16) for exotoxin A, and 4 (1:16) for elastase) | |||
| Sensitivity, % (95% CI) | 91 (70, 99) | 84 (62, 97) | 43 (22, 66) |
| Specificity, % (95% CI) | 9 (1, 32) | 24 (9, 49) | 38 (19,64) |
| Positive predictive value, % (95% CI) | 51 (34, 68) | 53 (35, 71) | 41 (22, 66) |
| Negative predictive value, % (95% CI) | 52 (7, 93) | 60 (24,91) | 39 (19, 64) |
| Using age-specific cutoffs as shown in Table 3 for cell lysate, exotoxin A, and elastase | |||
| Sensitivity, % (95% CI) | 52 (27, 73) | 49 (27, 73) | 36 (15, 59) |
| Specificity, % (95% CI) | 90 (68, 99) | 90 (68, 99) | 81 (56, 94) |
| Positive predictive value, % (95% CI) | 84 (52, 98) | 84 (52, 98) | 65 (31, 89) |
| Negative predictive value, % (95% CI) | 65 (44, 81) | 64 (44, 81) | 55 (36, 74) |
| Using a cutoff of 8 (1:256) as in West et al 12 paper | |||
| Sensitivity, % (95% CI) | 73 (48, 89) | 63 (38, 82) | 20 (6, 44) |
| Specificity, % (95% CI) | 43 (23, 68) | 57 (32, 77) | 81 (56, 94) |
| Positive predictive value, % (95% CI) | 56 (37, 77) | 60 (36, 79) | 51 (16, 84) |
| Negative predictive value, % (95% CI) | 61 (32, 84) | 60 (34, 80) | 50 (32, 68) |