Test Id : LEGRP
Legionella species, Molecular Detection, PCR, Varies
Useful For
Suggests clinical disorders or settings where the test may be helpful
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.
Method Name
A short description of the method used to perform the test
Rapid Polymerase Chain Reaction (PCR)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Fluoribacter bozemanae
Fluoribacter dumoffii
Legionella
Legionella sp
Legionella spp
Legionella bozemanae
Legionella dumoffii
Legionella gormanii
Legionella hackeliae
Legionella jordanis
Legionella longbeachae
Legionella micdadei
Legionella oakridgensis
Legionella pneumophila
Legionella wadsworthii
Legionellosis
Legionnaires disease
Legionella maceachernii
Legionella parisiensis
Legionella sainthelensi
Legionella cincinnatiensis
Legionella lansingensis
Legionella rubrilucens
Specimen Type
Describes the specimen type validated for testing
Varies
Necessary Information
Specimen source is required.
ORDER QUESTIONS AND ANSWERS
| Question ID | Description | Answers |
|---|---|---|
| SRC57 | Specimen Source |
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
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
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
See Specimen Required
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Tissue in formalin, formaldehyde, or acetone Formalin-fixed paraffin-embedded (FFPE) block | Reject |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Refrigerated (preferred) | 7 days | |
| Frozen | 7 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
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.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Not applicable
Interpretation
Provides information to assist in interpretation of the test results
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
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
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 birmhinghamensis and Legionella feeleii.
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.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Hayden RT, Uhl JR, Qian X, et al. Direct detection of Legionella species from bronchoalveolar lavage and open lung biopsy specimens: comparison of LightCycler PCR, in situ hybridization, direct fluorescence antigen detection, and culture. J Clin Microbiol. 2001;39(7):2618-2626. doi:10.1128/JCM.39.7.2618-2626.2001.
2. Diederen BM, Kluytmans JA, Vandenbroucke-Grauls CM, Peeters MF. Utility of real-time PCR for diagnosis of Legionnaires' disease in routine clinical practice. J Clin Microbiol. 2008;46(2):671-677. doi:10.1128/JCM.01196-07.
3. MacDonell MT, Colwell RR. The nucleotide sequence of the 5S rRNA from Legionella pneumophila. Nucleic Acids Res. 1987;15(3):1335. doi:10.1093/nar/15.3.1335
Method Description
Describes how the test is performed and provides a method-specific reference
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)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Sunday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
87801
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| LEGRP | Legionella PCR | 5020-3 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| SRC57 | Specimen Source | 31208-2 |
| 29515 | Legionella PCR, Result | 5020-3 |