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Legionella species, Molecular Detection, PCR, Varies

Test Codes

Epic: LAB1231885, Beaker: LegionPCR, MAYO: LEGRP

Department

Send Outs

Specimen Collection Criteria

Collection varies (see below).

Specimen Type: Lower respiratory
Sources: Bronchoalveolar lavage, bronchial aspirate/brushing/lavage/washing, tracheal/endotracheal secretions/aspirate, sputum
Container/Tube: Sterile container
Specimen Volume: 1.0 mL

Specimen Type: Fresh tissue or biopsy
Sources: Lung, pleura, heart valve, pericardium
Container/Tube: Sterile container
Specimen Volume: Entire collection or 5.0 mm(3) - approximately the size of a pencil eraser
Collection Instructions: Aseptically collect a 1.0 to 2.0 cm(3) piece of tissue whenever possible

Specimen type: Fluid
Sources: Pericardial, pleural, chest, chest tube drainage, thoracentesis, empyema
Container/Tube: Sterile container
Specimen Volume: 1.0 mL

Physician Office/Draw Specimen Preparation

Maintain specimen in sterile screw top container refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport:  Specimen in sterile screw top container, refrigerated (2-8°C or 36-46°F). 

Rejection Criteria

• Tissue in formalin, formaldehyde, or acetone.
• Formalin fixed paraffin-embedded (FFPE) block

In-Lab Processing

Maintain specimen in sterile screw top container at refrigerated (2-8°C or 36-46°F) prior to transport.

Transport: Specimen in sterile screw top container, refrigerated (2-8°C or 36-46°F). 

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F):
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:  7 days

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN.

Performed

Monday – Sunday
Results available in 3 days.

Reference Range

By report.

Test Methodology

Fluorescent resonance energy (FRET) hybridization.

Interpretation

A positive polymerase chain reaction (PCR) result for the presence of a specific sequence found within the Legionella 5S ribosomal RNA gene indicates the presence of a Legionella species DNA, which may be due to Legionella infection or environmental/water Legionella DNA in the specimen.

A negative PCR result indicates the absence of detectable Legionella DNA in the specimen but does not rule-out legionellosis as false-negative results may occur due to inhibition of PCR, sequence variability underlying the primers and probes, or the presence of Legionella species in quantities less than the limit of detection of the assay.

Clinical Utility

Legionnaires disease was first recognized during a pneumonia outbreak at the Legionnaires convention in Philadelphia in 1976. Investigators with the Centers for Disease Control and Prevention isolated a novel gram-negative bacillus, later named Legionella pneumophila. It is now widely recognized that L pneumophila (and other members of the genus Legionella) cause Legionnaires disease.

CPT Codes

87801

Contacts

Last Updated

4/15/2025