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HelpTest Code LEGRP Legionella species, Molecular Detection, PCR, Varies
Reporting Name
Legionella PCRUseful For
Sensitive and rapid diagnosis of pneumonia caused by Legionella species
The assay is not recommended as a test of cure because bacteria nucleic acids may persist after successful treatment.
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
VariesNecessary Information
Specimen source is required.
Specimen Required
The high sensitivity of amplification by polymerase chain reaction requires the specimen to be processed in an environment in which contamination of the specimen by Legionella DNA is unlikely.
Specimen Type: Lower respiratory
Sources: Bronchoalveolar lavage, bronchial aspirate/brushing/lavage/washing, tracheal/endotracheal secretions/aspirate, sputum
Container/Tube: Sterile container
Specimen Volume: 1 mL
Specimen Type: Fresh tissue or biopsy
Sources: Lung, pleura, heart valve, pericardium
Container/Tube: Sterile container
Specimen Volume: Entire collection or 5 mm(3) - approximately the size of a pencil eraser
Collection Instructions: Aseptically collect a 1 to 2 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 mL
Specimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Refrigerated (preferred) | 7 days | |
| Frozen | 7 days |
Reference Values
Not applicable
Day(s) Performed
Monday through Sunday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
87801
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| LEGRP | Legionella PCR | 5020-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| SRC57 | Specimen Source | 31208-2 |
| 29515 | Legionella PCR, Result | 5020-3 |
Clinical Information
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.
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.
Cautions
This assay does not differentiate between the Legionella species. False-positive results are theoretically possible if patient specimens are contaminated with Legionella DNA, which may occur since Legionella species are environmental organisms present in aquatic environments.
The following uncommonly encountered species of Legionella are not detected by this assay: Legionella anisa,  Legionella feeleii,  Legionella maceachernii,  Legionella parisiensis, and  Legionella sainthelensi.
Reject Due To
| Tissue in formalin, formaldehyde, or acetone Formalin-fixed paraffin-embedded (FFPE) block |
Reject |
Method Name
Rapid Polymerase Chain Reaction (PCR)
Report Available
3 daysForms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.