The utility of peanut components in the diagnosis of IgE-mediated peanut allergy among distinct populations.
BACKGROUND
Increasing data suggest that analysis of IgE to peanut components can be clinically helpful and possibly more accurate than IgE to whole peanut. Not all studies examining this topic, however, have used prospective samples, multiple components, and peanut challenges.


OBJECTIVE
We sought to determine the utility of peanut component testing, using a standardized, commercially available test done before oral peanut challenge in various populations of patients with suspected peanut allergy from 2 different countries.


METHODS
IgE to whole peanut and the recombinant allergen components Ara h 1, 2, 3, and 8 were analyzed from serum samples drawn before double-blind peanut challenge from 4 distinct cohorts of patients with suspected peanut allergy from 2 nations (United States and Sweden).


RESULTS
Patients (n = 167; median age, 11.7 years; interquartile range, 7.0-15.0 years) had serum analyzed for peanut components and completed an oral food challenge to peanut. Although IgE to peanut was the most sensitive test (0.93), Ara h 2 was the most specific (0.92) and provided the best positive predictive value (0.94) of all the tests. Ara h 2 was also the best overall diagnostic test by receiver operating characteristic analysis (area under the curve, 0.84; P < .05).


CONCLUSIONS
In patients with suspected peanut allergy, IgE to peanut is a sensitive test but is not specific. IgE to Ara h 2 is a more specific and more accurate diagnostic test in this sampling of patients with suspected peanut allergy. Given each tests attributes, a stepwise approach to testing may provide clinicians with a way to minimize the need for peanut challenges.
Elliot and Roslyn Jaffe Food Allergy Institute, Division of Allergy and Immunology, Department of Pediatrics, Mount Sinai School of Medicine, New York, NY.
Jay A
JA
Lieberman
Susanne
S
Glaumann
Sofia
S
Batelson
Magnus P
MP
Borres
Hugh A
HA
Sampson
Caroline
C
Nilsson
D000293:Adolescent; D002648:Child; D015331:Cohort Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D021183:Peanut Hypersensitivity / Q000097:blood* / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013548:Sweden; D014481:United States
D007073:Immunoglobulin E
Anaphylaxis; Ara h 1; Ara h 2; Ara h 3; Ara h 8; Food allergy; IQR; Interquartile range; OFC; Oral food challenge; Peanut allergy; Peanut sensitization; ROC; Receiver operating characteristic; SPT; Skin prick test