3.2. Comparison of the methods
The results of the MSD multiplex immunoassay were compared to the two
most commonly used tests: the SPT and the ImmunoCAP assay, performed by
a clinical laboratory. When an individual scored positive for the
allergy it is shown in colour in Figure 1. When redness of the skin is
observed in the SPT, it is indicated as positive. For the tests of the
clinical lab and the MSD immunoassay, a threshold of 0.10 kU/L was used;
a result above this threshold was considered positive. Both individual
allergens and mixes of allergens were tested in parallel. The SPT
measurements of subject 16 were excluded because this individual reacted
to all pricks, including the negative control, which makes the results
doubtful. This could be due to aspecific hyperreactivity of the skin.
Most results corresponded well between the three tests, although there
were some differences, as discussed later.