Legionella pneumophila Antibody (Type 1), IgG by IFA
0050376
Ordering Recommendation
Provide retrospective evidence of suspected Legionella pneumophila infection.
Mnemonic
LEGAB IFA
Methodology
Semi-Quantitative Indirect Fluorescent Antibody
Performed
Mon-Fri
Reported
1-4 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
- Patient Preparation
- 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.
- Remarks
- Stability
- 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 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.
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.
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.
Components
| Component Test Code* | Component Chart Name | LOINC |
|---|---|---|
| 0050376 | Legionella Type 1 By IFA, IgG | 9541-4 |
Aliases
- Legionella pneumophila
- Legionnaires Disease Testing