ARUP's Laboratory Test Directory
| 0050376: Legionella pneumophila Antibody (Type 1), IgG by IFA |
| Test Mnemonic: LEGAB IFA | |
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Methodology: Indirect Fluorescent Antibody
Performed: Mon-Fri Reported: 1-4 days |
| Specimen Required: | |
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Collect: One 4 mL SST.
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) |
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| Reference Interval: |
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< 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: | |
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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 |