DIAGNOSTIC PERFORMANCE OF DIFFERENT METHODS FOR DETECTION OF SENSITIZATION TO PRU P 3 IN SPAIN

The skin prick test (SPT) is a simple and sensitive technique for detecting sensitization to food allergens. 373 patients from previous studies of plantfood allergy in Spain were reviewed restrospectively. SPT with LTP extract (ALK-Abelló®) and specific IgE(sIgE) to Pru p 3(ImmunoCAP-Thermofisher or ISAC 103 or 112 Microarray) were performed in all of them. We sought to determine the frequency of positive(area>7mm2) SPT to LTP(SPT-LTP) measured by planimetry and sIgE against Pru p 3(Immunocap>0.35 kUA/L; ISAC>0.3 ISU) with the presence of symptoms. Diagnostic performance of SPT-LTP was compared with determination of sIgE by in vitro techniques. The ratio SPT-LTP/SPT-histamine diagnostic accuracy was compared with the determination sIgE. In the studied population, 192(52%) were male and 180(48%), female. Mean age:31,3 (29,8-32,8) y.o. Among them, 244(67%) presented positive SPT-LTP and 121(33%) had negative SPT-LTP;168(45%) subjects showed sIgE to Pru p 3(CAP). SPT-LTP showed good correlation with determination of sIgE to Pru p 3 by ImmunoCAP(0.748) or either by ISAC(0.838). Seventy nine (32%) were allergic to peach, whereas 166(68%) tolerated it; tolerance was unknown in 128 patients. SPT-LTP wheal size was greater in allergic patients than in tolerating ones (P=0.0001). Cut-off point for detecting sensitization to Pru p 3 was 29mm2(S:57.9%;E:88.8%) for SPT-LTP’s wheal size and 0.37 kUA/L(s:68.5%;E:75.9%) for sIgE(ImmunoCAP). ROC curves for SPT-LTP/SPT-histamine and SPT-LTP/sIgE(CAP) showed similar AUC (0.78 and 0.75 respectively). In our population, SPT-LTP showed good correlation with the studied in vitro techniques. SPT-LTP and determination of sIgE showed similar diagnostic accuracy in detecting sensitization to Pru p 3.