Table IV.
Testing the proposed approach to using the basophil activation test to diagnose nut and sesame seed allergies
| Outcome of history SPT, sIgE to extracts and components | Misdiagnosis | Outcome of BAT | Outcome of OFC and misdiagnosis | Correct diagnosis—% total patients | Nr BATs required—% total patients | Total OFCs—with BAT (without BAT) and % reduction | Positive OFCs with BAT (without BAT) and % reduction | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cashew nut allergy | NA | 29 | 13 | FN = 0 | FN = 0 | |||||||||||||
| Equivocal | 27 | 17 | NR or intermediate | 8 | 6 | 2 1 | CA | 99% | 98% | 31% | 29% | 11% | 6% | 75% | 50% | |||
| Negative | 16 | 10 | FN = 0 | 0 | 87/88 | 57/58 | 27 | 17 | 24 (27) | 16 (17) | 2 (8) | 1 (2) | ||||||
| Positive | 3 | 1 | FP = 0 | 0 | ||||||||||||||
| Allergic | 32 | 28 | FP = 1 | FP = 1 | ||||||||||||||
| Sesame seed allergy | NA | 50 | 14 | FN = 0 | FN = 0 | |||||||||||||
| Equivocal | 35 | 13 | NR or intermediate | 4 | 2 | 1 | 1 SA | 99% | 100% | 39% | 45% | 11% | 15% | 50% | 50% | |||
| Negative | 27 | 8 | FN = 3 | 2 | 88/89 | 29/29 | 35 | 13 | 31 (35) | 11 (13) | 4 (8) | 3 (6) | ||||||
| Positive | 4 | 2 | FP = 1 | 0 | ||||||||||||||
| Allergic | 4 | 2 | FP = 0 | FP = 0 | ||||||||||||||
| Almond allergy | NA | 69 | 40 | FN = 0 | FN = 0 | |||||||||||||
| Equivocal | 19 | 17 | NR or intermediate | 4 | 4 | All | NA | 100% | 100% | 21% | 29% | 5% | 6% | 75% | 50% | |||
| Negative | 14 | 12 | FN = 1 | 1 | 89/89 | 58/58 | 19 | 17 | 18(19) | 16 (17) | 1 (4) | 1 (2) | ||||||
| Positive | 1 | 1 | FP = 0 | 0 | ||||||||||||||
| Allergic | 1 | 1 | FP = 0 | FP = 0 | ||||||||||||||
| Hazelnut allergy | NA | 17 | 7 | FN = 0 | FN = 0 | |||||||||||||
| Equivocal | 59 | 38 | NR or intermediate | 32 | 22 | 15 | 12 HA | 98% | 100% | 67% | 70% | 0% | 0% | 0% | 0% | |||
| Negative | 27 | 16 | FN = 1 | 1 | 86/88 | 54/54 | 59 | 38 | 59 (59) | 38 (38) | 15 (15) | 13 (13) | ||||||
| Positive | 0 | 0 | FP = 0 | 0 | ||||||||||||||
| Allergic | 12 | 9 | FP = 0 | FP = 1 | ||||||||||||||
| Peanut allergy | NA | 9 | 2 | FN = 0 | FN = 0 | |||||||||||||
| Equivocal | 34 | 17 | NR or intermediate | 7 | 3 | All | NA | 97% | 96% | 39% | 36% | 15% | 12% | 60% | 33% | |||
| Negative | 22 | 12 | FN = 2 | 2 | 85/88 | 45/47 | 34 | 17 | 29 (34) | 15 (17) | 2 (5) | 2 (3) | ||||||
| Positive | 5 | 2 | FP = 2 | 1 | ||||||||||||||
| Allergic | 45 | 28 | FP = 1 | FP = 1 | ||||||||||||||
BAT, Basophil activation test; CA, cashew nut allergic; FN, false-negative; FP, false-positive; HA, hazelnut allergic; NR, nonresponder; OFC, oral food challenge; SA, sesame seed allergic; sIgE, specific IgE; SPT, skin prick testing.
Numbers in bold indicate the results for the whole population, and numbers in italic refer to the subgroup who were actually challenged to the individual nuts as part of the Pronuts study. Allergic patients had results at or above the 95% positive predictive value (PPV) cutoff or a combination of above the 95% negative predictive value (NPV) and above the 95% PPV; nonallergics had below the 95% NPV for all tests; and equivocal were the remaining cases.
Subjects with results for all tests were included, including subjects with nonresponder basophils: n = 88 for hazelnut, n = 88 for peanut, n = 88 for cashew, n = 89 for almond, n = 89 for sesame.