what is a rapid antigen detection test and why is it important?

Answer 1

Depends what test you are referring to. Generally Rapid Antigen Tests are dry chemistry, portable, easy-to-use tests, With regard to the rapid Malarial antigen test, there are the benefits of a definite result in about 15 minutes, little training required, no machinery or microscopes needed, cheap setup costs, you can do them anywhere (you don't need to be in a laboratory). The main disadvantage is the on-going costs, they tend to be expensive for each test.
Here is a site with some info.

Answer 2

These are Immunosorbent assays that can be life savers. Favorable prognosis for many diseases require early treatment. A good example is malaria. A couple of days could make a difference between life and death for malaria patients. These rapid tests allow preliminary diagnosis in order to at least start treatment.