Legionella sp antibodies - serum

Last updated: Tuesday, 07, August, 2007

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Item Process
Specimen

5-10 mL blood in plain tube, collected at onset of disease and 4-6 weeks later (convalescent).

Method

IFA.

Application

Investigation of pneumonia.

Fever.

Interpretation

Confirmation of legionella infection depends on detecting a four-fold increase in titre to ≥128. A single titre of ≥256 is suggestive of infection.

Polyvalent antiserum is used to detect antibodies to serogroups 1-6 of L. pneumophila.

Monovalent antisera are used to identify antibodies to other species, eg, L. longbeachae, L. micdadei.

Seroconversion may take up to 6 weeks. A convalescent sample is required for optimal diagnosis.

Reference

Murdoch DR. Clin Infect Dis 2003; 36: 64-69.

Waterer GW et al. Am J Med 2001; 110: 41-48.