ARUP's Laboratory Test Directory

Legionella pneumophila Antibody (Types 1-6), IgG by IFA : 0050365

Mnemonic: LEGAB

Methodology: Semi-Quantitative Indirect Fluorescent Antibody
Performed: Mon-Fri
Reported: 1-4 days
Specimen Required: Collect: 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: Refrigerated.

Unacceptable Conditions: Contaminated, hemolyzed, or severely lipemic specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
Reference Interval:
<1:128  Negative -  No significant level of Legionella pneumophila Type 1-6 IgG antibody detected.
1:128 Equivocal - Questionable presence of Legionella pneumophila Type 1-6 IgG antibody detected. Repeat testing in 10-14 days may be helpful.
1:256 or greater Positive -  Presence of Legionella pneumophila Type 1-6 IgG antibody detected, suggestive of current or past infection.
Interpretive Data: Seroconversion between acute and convalescent sera is considered strong evidence of recent infection.  The best evidence for infection is a significant change on two appropriately timed specimens where both tests are done in the same laboratory at the same time.  This assay may detect infection by any of the serotypes 1-6.  The CDC and many state health laboratories recommend testing only for antibody to Legionella pneumophila Type 1.  For equivocal or positive IFA results, the CDC protocol suggests follow-up testing for Legionella pneumophila antibody Type 1.
Note: For follow-up testing on equivocal or positive results, refer to Legionella pneumophila Antibody (Type 1), IgG by IFA (0050376).
CPT Code(s): 86713