Can one be tested for Legionella after the pneumonia has been cured?

Can you test for Legionnaires’ disease after you have been treated and the pneumonia has subsided?

A blood test, antibody serology, can be performed. It is most accurate 4-12 weeks after the pneumonia. The ideal circumstance is to have a blood test obtained during the pneumonia (acute sera) followed by a repeat test 4-12 weeks later (convalescent sera). Another test is the urinary antigen test, but the accuracy of this test decreases 1 month after the pneumonia.