Legionella pneumophila Antibody Level

CERNER / EPIC MNEMONIC: LEGION AB
POE DESCRIPTION: LEGIONELLA PNEUMOPHILA AB; LEGION AB
CPT CODE: 86713-90
TURNAROUND TIME: 2-7 working days
SPECIAL INSTRUCTIONS: It is the responsibility of the ordering physician to see that both acute and convalescent specimens are obtained. The physician should arrange for the collection of the convalescent serum 14 days after the acute is collected.
CONTAINER TYPE:

Red top Vacutainer® tube or SST tube

SPECIMEN REQUIREMENTS:

2.0 mL blood (1.0 mL serum)

REJECTION CRITERIA: Excessive hemolysis, gross contamination of specimen, chylous serum, improper storage of specimen, inappropriate specimen container, insufficient specimen volume.
MINIMUM VOLUME: 1.0 mL blood (0.5 mL serum)
REFERENCE RANGE:

See Specialty Labs - Search Test Code 8246

LIMITATIONS OF TEST: A negative antibody response does NOT rule out infection with Legionella pneumophila serogroups 1-6. False negative results may occur when samples are drawn too early after onset. It may take up to 9 weeks postinfection for seroconversion. False negative results may also occur due to the lack of antibody acquisition. Only 80% of L. pneumophila culture proven infections develop diagnostic changes in antibody titer. A positive antibody response may be due to cross reacting antibody found in patients with non-Legionella infections. Pneumonia and bacteremia caused by Pseudomonas species, Haemophilus species, Enterobacteriaceae, Bordetella species, Chlamydia, Rickettsia, Bacteroides species, M. tuberculosis and other mycobacteria, Citrobacter species, and Leptospirosis have been shown to cause false positive results in Legionella serology. Due to the background prevalence rate in some populations, a single positive serum titer cannot be construed to constitute a L. pneumophila infection. Therefore, paired sera analysis and Legionella culture or urinary antigen testing should be performed to aid with diagnosis. Cross reactivity may occur with sera with infections due to other Legionella species.
METHODOLOGY: Enzyme immunoassay (EIA)
TEST SYNONYM(S):Legionella Antibody; Legionnaires` Disease Serology