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Test Code LAB5343 Legionella species, Molecular Detection, PCR, Varies

Important Note

Mayo's test code: LEGRP

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Legionella PCR

Specimen Type

Varies


Necessary 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


Reject Due To

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

Specimen Stability Information

Specimen Type Temperature Time
Varies Refrigerated (preferred) 7 days
  Frozen  7 days

Specimen Minimum Volume

See Specimen Required

Day(s) Performed

Monday through Sunday

Specimen Retention Time

7 days

Report Available

3 days

Reference Values

Not applicable

Useful 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.

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

Method Description

This method employs a target-specific detection system using fluorescent resonance energy transfer (FRET) hybridization probes designed for a specific sequence found within the Legionella 5S ribosomal RNA gene. The LightCycler (LC) instrument amplifies and monitors target nucleic acid sequences by fluorescence during polymerase chain rection (PCR) cycling. This is an automated PCR system that can rapidly detect amplified product development through stringent air-controlled temperature cycling. The detection of amplified products is based on the FRET principle. For FRET product detection, a hybridization probe with a donor fluorophore, fluorescein, on the 3' end is excited by an external light source, which emits light that is absorbed by a second hybridization probed with an acceptor fluorophore, LC-Red 640, on the 5' end. The acceptor fluorophore then emits light of a different wavelength that can be measured with a signal that is proportional to the amount of specific PCR product. The detection process is completed in a closed system.(Cunningham SA, Sloan LM, Uhl JA, et al. Validation of a real-time PCR assay for the detection of Legionella species in respiratory samples. Abstracts of the Annual Meeting of the Association for Molecular Pathology, 2009 General Meeting, Nov. 19-22, 2009; Rucinski SL, Murphy MP, Kies KD, Cunningham SA, Schuetz AN, Patel R. Eight years of clinical Legionella PCR testing illustrates a seasonal pattern. J Infect Dis. 2018;218(4):669-670. doi:10.1093/infdis/jiy201)

Supportive Data

In a Mayo Clinic study, 153 archived respiratory specimens previously tested for Legionella species by direct fluorescence antibody (DFA) testing were extracted and tested using this polymerase chain reaction (PCR) method. The PCR assay was 100% sensitive and 99.3% specific, in comparison to DFA. Additionally, 30 lung tissues and 30 pleural fluids were spiked with 3 of the most frequently isolated Legionella species. Spiking studies showed similar analytical sensitivity for PCR and the DFA method. The analytical sensitivity was less than 50 targets/20 microliter reaction. No cross-reactivity was observed when tested on a panel of respiratory pathogens or normal flora bacteria of the upper respiratory tract. Fifteen serogroups of Legionella pneumophila (L pneumophila serogroups 1-14, 15/16) and 15 additional Legionella species; (Fluoribacter [Legionella] bozemanae, Fluoribacter [Legionella] dumoffii, Legionella gormanii, Legionella jordanis, Legionella longbeachae, Legionella micdadei, Legionella oakridgensis, Legionella hackeliae, Legionella maceachernii, Legionella parisiensis, Legionella sainthelensi, Legionella cincinnatiensis, Legionella lansingensis, Legionella rubrilucens, and Legionella wadsworthi) included in the panel were detected with the PCR method.

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.