Results analysis and statistics
Analytical correlations and general agreement between NOVEOS and
ImmunoCAP were calculated by using the Spearman’s formula, Cohen‘s kappa
index, and percentage of agreement (proportion of both true positive and
true negative results). Clinical performance of specific IgE values was
determined through odd-ratios (OR; Baptista-Pike’s confidence intervals)
and relative risks (RR; C.I. according to Koopman’s asymptotic score) of
presenting with allergy, and also through calculation of receiver
operator curves (ROC), kappa index, and percentages of agreement. For
these analyses, individuals were categorized for each allergen and
technique into four groups: “true positives” (confirmed allergy and
sIgE above the cut-off value for the relevant allergen), “true
negatives” (confirmed tolerance and sIgE below the cut-off value for
the relevant allergen), “false negative” (confirmed allergy and sIgE
below the cut-off value for the relevant allergen), and “false
positive” (confirmed tolerance and sIgE above the cut-off value). All
statistical calculations were performed by using PRISM 9 (GraphPad
Software, San Diego, California USA,www.graphpad.com). Significance
was set at p>0.05. Optimal cut-off of sIgE values were
calculated using Youden’s index (21).