Allergy test? Well, you actually can test yourself at home. If you approach a cat and you start sneezing then obviously you're allergic to cats. If you eat seafood and start itching whole body, obviously you have allergies to seafood.

You can test if you've allergies to antibiotics (e.g. penicillin) though... But why is it necessary to identify your allegens in clinic when you can identify at home?