ARUP's Laboratory Test Directory

Legionella pneumophila Antibody (Type 1), IgG by IFA : 0050376

Mnemonic: LEGAB IFA

Methodology: Indirect Fluorescent Antibody
Performed: Mon-Fri
Reported: 1-4 days
Specimen Required: Collect:  One 4 mL serum separator tube.

Transport:  1 mL serum at 2-8°C. (Min: 0.5 mL)  Submit specimen in an ARUP Standard Transport Tube.

Pediatric Collection/Transport:  0.15 mL serum at 2-8°C.

Remarks:  Separate serum from cells ASAP. Acute and convalescent specimens must be labeled as such; parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Please mark specimen plainly as "acute" or "convalescent."

Unacceptable Conditions:  Severely lipemic, contaminated, or hemolyzed specimen
s.

Stability:  After separation from cells: Ambient: 2 days; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
Reference Interval:
< 1:128  Negative - No significant level of Legionella pneumophila Type 1 IgG antibody detected.
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.
Interpretive Data: The CDC and many state health laboratories recommend testing only for antibody to Legionella pneumophila Type 1. 

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.
CPT Code(s): 86713
 
 

 

 

 
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