Legionella IgG (IFA)
Sample: Serum
Schedule: Daily (Immunofluorescence)
Units: Titer Range: Positive IgG indicates past infection
Remarks: Legionella is often found in the filters of air conditioned systems. More than 30 species have been reported, but Legionella pneumophila serogroup 1 is responsible for most infections in humans. Atypical pneumonia is often associated with systemic manifestations. It is responsible for 10% ofcases of pneumonia acquired in both the commimity and hospitals. During the infection, an immune response is produced against the L. pneumophila group related antigen. In the serological diagnosis of the disease, the only standardized technique is Indirect Immunofluorescent Assay (IFA). It is necessary to prove seroconversion inorder to confirm a serological diagnosis since high titres may be found in healthy population. A igh titre in single serum sample together with clinical symptoms suggests illness. The use of pools of different Legionella serogroups shows seroconversions that are not confirmed with monovalent antigens. L. pneumophila serogroup 1 antigen alone should enable the serological diagnosis of most cases of Legionnaires disease and avoid false positive results. This test is part of the Pneumonia Panel Group wich includes the most important etiological agents of infectious diseases of the respiratory systrem: Legionella pneumophila, Mycoplasma pneumoniae, Coxiella burnetti, Chlamydia pneumoniae, Adenovirus, R.S.V., Influenza A, Influenza B and Parainfluenza (serotypes 1,2,3).
