Legionella Species Detection and Limited Differentiation by Multiplex Real-Time PCR
Test Mnemonic
LEGPCR
CPT Codes
- 87541 - QTY (1)
LOINC ®
21363-7
Aliases
- Legionella pneumophila
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 3 mL | Bronch (BAL) | Sterile container | Ambient | Collect and submit the specimen in a sterile container (ie. Oracle #1012787, Covidien #2200SA). If aliquoting is necessary, sterile tubes must be used. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Sputum, induced | Sterile container | Collect and submit the specimen in a sterile container (ie. Oracle #1012787, Covidien #2200SA). If aliquoting is necessary, sterile tubes must be used. | ||
| 1 mL | Aspirate, tracheal | Sterile container | Collect and submit the specimen in a sterile container (ie. Oracle #1012787, Covidien #2200SA). If aliquoting is necessary, sterile tubes must be used. | ||
| 1 mL | Washings, bronch | Sterile container | Collect and submit the specimen in a sterile container (ie. Oracle #1012787, Covidien #2200SA). If aliquoting is necessary, sterile tubes must be used. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 24 hours |
| Refrigerated | 7 days |
| Frozen | 30 days |
Days Performed
6 days per week
Turnaround Time
3 days
Methodology
| Name | Description |
|---|---|
| Polymerase Chain Reaction (PCR) |
Reference Range
| Legionella species DNA | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Not Detected |
Special Info
Test performed Monday through Friday and Saturday or Sunday.
Clinical Info
Legionella are an important cause of community-acquired pneumonia, and are associated with diseases known commonly as Legionnaire’s disease and Pontiac Fever. Legionella species are found naturally in freshwater environments and can cause outbreaks when they grow in human-made water systems like indoor plumbing systems and cooling towers. The diseases associated with Legionella infection, known collectively as legionelloses, are generally caused by exposure to such contaminated water. The rapid and accurate detection of Legionella species in lower respiratory specimens is important for tailoring antimicrobial therapy and for epidemiologic investigation. Bacteriologic culture of these gram-negative bacilli requires specialized media, and is slow and relatively insensitive compared to molecular methods. Legionella urine antigen testing is a rapid and less-invasive method for diagnosis, but is only reliably positive in Legionella pneumophila serogroup 1 (sg1) infections. Real-time polymerase chain reaction (RT-PCR) is a fast and sensitive method to detect Legionella species in respiratory samples. This multiplex RT-PCR assay originally published by the Centers for Disease Control (CDC) simultaneously detects Legionella species, and differentiates between Legionella species (ssrA gene), L. pneumophila (mip gene), and L. pneumophila serogroup 1 (wzm gene).
Clinical Limitation
This assay is intended for use as a lab-developed test for the qualitative simultaneous detection and differentiation of Legionella spp., L. pneumophila and L. pneumophila sg1 from lower respiratory specimens. It is meant to be used as an aid in diagnosis of legionellosis, in conjunction with other clinical and laboratory information. Based on the methodology, the assay may be falsely negative in cases with very low bacterial burden, or caused by uncommon Legionella species. It may be falsely positive in cases of upper airway colonization/contamination, or transient/remnant presence of nucleic acid. Specimens positive for Legionella spp. by this assay will be reflexed to culture for attempted isolation of the organism, with results reported separately.
Clinical Reference
Benitez AJ, Winchell JM. Clinical application of a multiplex real-time PCR assay for simultaneous detection of Legionella species, Legionella pneumophila, and Legionella pneumophila serogroup 1. J Clin Microbiol. 2013 Jan;51(1):348-51. doi: 10.1128/JCM.02510-12. Epub 2012 Nov 7. Erratum in: J Clin Microbiol. 2014 Feb;52(2):709. PMID: 23135949.