How is Legionnaires’ disease diagnosed?
Specialized laboratory tests are necessary and,
unfortunately, may not be available in many hospitals. These
include culture on specialized
Legionella media. Culture media furnish
nutrients for the bacterium. When sputum from the patients is
placed onto the culture media, the bacterium grows on the medium
and can be identified.
Other tests include direct fluorescent antibody (DFA) in
which the bacterium can be stained and becomes visible under a
fluorescent microscope. Antibody testing is a blood test in which
antibodies that are reactive
against Legionella are present in
the human body showing that the patient has come into contact with
the bacterium previously. Urinary antigen is a test that
detects Legionella in the
urine.