- The short answer is that both complement each other. There are defined circumstances where one test will perform better than the other. Thus, if a child skin is covered in eczema it may be too distressing for the child and inaccurate to do skin prick testing. Here blood testing is the test of choice.
- Similarly, if a child is on antihistamine medication, blood testing is more helpful as the skin will not react. In contrast, if a child is very allergic and has a high total IgE level, blood testing may produce a high number of falsely elevated results especially to foods such as wheat and soy (so called false positives). Furthermore, skin prick testing allows one to assess the difference in reactivity between a cooked food allergen and a raw food allergen.
- There are frequent situations where it is helpful to follow both. For example, reduction in both skin tests and blood tests over time is helpful in monitoring the resolution of an allergy.
