Provide retrospective evidence of suspected Legionella pneumophila infection.
- Patient Preparation
- Serum separator tube.
- Specimen Preparation
- Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.1 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Mark specimens plainly as "acute" or "convalescent."
- Storage/Transport Temperature
- Unacceptable Conditions
- Contaminated, hemolyzed, or severely lipemic specimens.
- After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
1:128 Equivocal - Questionable presence of Legionella pneumophila Type 1 IgG antibody detected. Repeat testing in 10-14 days may be helpful.
1:256 or greater Positive - Presence of Legionella pneumophila Type 1 IgG detected, suggestive of current or past infection.
A fourfold rise in titer greater than 1:128 from the acute to the convalescent phase provides evidence of a recent infection with Legionella. A standing or single titer greater than or equal to 1:256 suggests past exposure or infection, but is inconclusive for diagnosis. Single titers of less than 1:256 are not considered evidence of infection. Diagnosis of acute infection can only be made with a fourfold or greater rise in titer between acute and convalescent specimens.
|Component Test Code*||Component Chart Name||LOINC|
|0050376||Legionella Type 1 By IFA, IgG||9541-4|
- Legionella pneumophila
- Legionnaires Disease Testing