Daniel, who usually suffers from seasonal hay fever, has had a runny nose and a sore throat since the last couple of days. Although he took some antihistamines, it did not alleviate his symptoms, and...

Daniel, who usually suffers from seasonal hay fever, has had a runny nose and a sore throat since the last couple of days. Although he took some antihistamines, it did not alleviate his symptoms, and he wonders if he has contracted the common cold. By checking Daniel’s blood antibody levels, how will his physician be able to decide if Daniel has an allergic reaction or a cold?