Table 2. Validation of SULF-FAST in All Validation Cohorts (Overall) With Subgroup Analysis Performed on Allergy Phenotypea.
| Characteristic | Melbourne, Australia | Nashville, Tennessee | ||||||
|---|---|---|---|---|---|---|---|---|
| Overall (N = 116) | Immediate (n = 32) | Delayed (n = 41) | Unknown (n = 43) | Overall (N = 204) | Immediate (n = 23) | Delayed (n = 106) | Unknown (n = 75) | |
| No. (%) with SULF-FAST score ≥3 | 8 (6.9) | 0 | 8 (19.5) | 0 | 25 (12.3) | 7 (30.5) | 14 (13.2) | 4 (5.3) |
| No./total No. (%) with SULF-FAST score ≥3 with positive test result | 4/8 (50) | NA | 4/8 (50) | NA | 5/25 (20) | 2/7 (28.6) | 3/14 (21.4) | 0/4 (0) |
| Validation AUC (95% CI) | 0.82 (0.61-1.00) | NA | 0.78 (0.56-0.99) | NA | 0.64 (0.5-0.78) | 0.71 (0.37-1.00) | 0.61 (0.44-0.78) | 0.47 (n/a) |
| Sensitivity, % (95% CI) | 66.7 (22.3-95.7) | NA | 66.7 (22.3-95.7) | NA | 38.5 (13.9-68.4) | 66.7 (9.4-99.2) | 33.3 (7.5-70.1) | 0 (0-97.5) |
| Specificity, % (95% CI) | 96.4 (91.0-99.0) | NA | 88.6 (73.3-96.8) | NA | 89.5 (84.3-93.5) | 75 (50.9-91.3) | 88.7 (80.6-94.2) | 94.6 (86.7-98.5) |
| PPV, % (95% CI) | 50.0 (15.7-84.3) | NA | 50 (15.7-84.3) | NA | 20.0 (6.8-40.7) | 28.6 (3.7-71.0) | 21.4 (4.7-50.8) | 0 (0-60.2) |
| NPV, % (95% CI) | 98.1 (93.5-99.8) | NA | 93.9 (79.8-99.3) | NA | 95.5 (91.4-98.1) | 93.8 (69.8-99.8) | 93.5 (86.3-97.6) | 98.6 (92.4-100) |
Abbreviations: AUC, area under the curve for S-FAST score 3 or higher; NA, not applicable; NPV, negative predictive value; PPV, positive predictive value.
a
Immediate phenotype was defined as any reaction that occurred within 1 hour after exposure to initial medication dose, whereas delayed phenotype was defined as any reaction occurring beyond 1 hour, including those after multiple medication doses. Unknown phenotype includes any reaction that was nonimmune mediated and reactions with unknown timeline.