Legionella DNA detection by PCR

General Information

Lab Name

Lab Code

LEGDNA

Epic Ordering

Legionella DNA detection by PCR

Description

Detection and identification Legionella pneumophila and other Legionella species.

Legionella species are slow growing fastidious gram-negative organisms that are ubiquitous in the environment. Most exposures which lead to human disease are waterborne, primarily due to inhalation of water droplets from contaminated potable water. Inhalation of water droplets containing Legionella can lead to severe lower respiratory infection (pneumonia) known as Legionnaire's disease. While Legionella is a cause of community acquired pneumonia, it can also be acquired from hospital water systems. Certain populations are at particularly high risk of developing this disease, including those with underlying chronic illness with a high mortality rate among immunocompromised patients. Early diagnosis is key to preventing Legionella-associated mortality.

Rapid urinary assays used to detect Legionella are specific only for L. pneumophila serotype 1, while culture methods require special media and Legionella species is often slow to grow. The LEGDNA (Legionella PCR) is a real-time PCR assay targeting 16S rRNA gene followed by sequence analysis which detects and identifies Legionella pneumophila and other Legionella spp.

For more information on this test, to download a requisition form, and for a list of acceptable and unacceptable specimens, please refer to: Molecular Diagnosis Microbiology Section Website

Synonyms

16S PCR, Legionella identification, Legionella PCR, Legionella sequencing, legionellosis PCR, Legionnaires’ Disease, molecular Legionella, universal PCR

Components

Code	Name
LG16RS	Legionella PCR: Detection, 16S rRNA
LG16ID	Legionella PCR: Identification, 16S rRNA
LEGSI	Legionella PCR: Specimen Description
LEGSPI	Legionella PCR: External Identifier
LEGSR	Legionella PCR: Special Requests
LEGSC	Legionella PCR: Specimen Comments
LEGNAE	Legionella PCR: Specimen DNA Extraction
LEGREV	Legionella PCR: Pathologist Review
LEGME	Legionella PCR: Method Note

Interpretation

Method

DNA extraction, nucleic acid purification, polymerase chain reaction (PCR), sequencing

Reference Range

See individual components

Guidelines

Ordering & Collection

Specimen Type

Tissue (Fresh frozen or paraffin-embedded), Fluid (see Acceptable Specimens for details)

Collection

Acceptable specimens are listed below. Please see this page for complete specimen collection and handling instructions.

Specimens should be collected into a DNA free container labeled with at least two identifiers.

Acceptable Specimens

Fresh frozen tissue
Fresh frozen fluid: any body fluid is acceptable if it is not listed under Unacceptable Specimens. See common examples below.
Formalin Fixed Paraffin-embedded tissues (FFPE, PET): blocks, scrolls, and unstained slides are acceptable
eSwabs and UTM (universal transport media)

Common acceptable body fluid examples: cerebrospinal fluid, pleural fluid, pericardial fluid, urine, bronchial lavage, joint fluid, bone marrow, vitreous fluid, etc.

Additional Acceptable Specimens

Sputum

Unacceptable Specimens

Blood, serum, plasma, stool
No citrated or heparinized solutions
No SPS (Sodium Polyanethole Sulfonate) e.g. Wampole Isolator Tubes
Tissues floating in formalin
Swab/fluid collected in tube containing agar

Handling Instructions

Fresh frozen tissue/fluid specimens should be submitted and maintained on dry ice.

Formalin Fixed Paraffin-embedded tissues (FFPE, PET) can be sent ambient or with ice packs during warmer summer months to prevent melting.

Optimal Quantity:

Fresh Tissue: 0.3-1.0 cm^3
Fluid: 0.2-1 mL
Formalin Fixed Paraffin-embedded Tissue (FFPE/PET): blocks are preferred and will be sent back to client upon completion of testing
Scrolls/unstained slides: cross-sectional area >1cm^2 send 10 sections of 10µm thickness, if <1cm^2 send 20 sections if available

Please note: We do not need a separate specimen aliquot for each test ordered. Only a single specimen aliquot or block of optimal quantity is necessary for performing multiple tests. If multiple aliquots or blocks of optimal quantity are sent, up to 2 will be pooled.

Quantity

requested: See Optimal Quantity above
minimum: Specimens below optimal quantity are acceptable for testing, however, diagnostic yield is generally proportional to specimen size.

Processing

Processing: UWMC/HMC – store and send specimen refrigerated and freeze specimens at -20°C upon arrival in UW-ML Microbiology. If specimen storage and transport will exceed 8 hours, freeze at -20°C.

Freeze specimens at -20°C upon arrival

Outside Laboratories: Freeze specimens in sterile containers at -20°C. Transport all specimens on dry ice.

Performance

LIS Dept Code

Micro Molecular Diag (MMD)

Performing Location(s)

UW-MT	Microbiology, Molecular Diagnostics 206-520-4600 Clinical Lab, Room # NW177, University of Washington Medical Center, 1959 NE Pacific street, Seattle, WA 98195

Frequency

Fresh frozen tissues/fluids result in 2-3 business days after receipt of specimen. Formalin Fixed Paraffin-embedded tissues result in 3-4 business days after receipt of specimen.

Available STAT?

Billing & Coding

CPT codes: 87801
LOINC: 49616-6
Interfaced Order Code: UOW4372