A nurse is preparing to administer a Mantoux skin test to a client. The nurse should inform the client that the purpose of the Mantoux skin test using purified protein derivative (PPD) is to do which of the following?
1) Identify clients who lack immunity to tuberculosis
2) Find out if a client has active tuberculosis
3) Decrease hypersensitivity to purified protein derivative
4) Identify clients who have been infected with Mycobacterium tuberculosis
