Leishmania species DNA detection by PCR

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General Information

Lab Name
Leishmania Species DNA Detection
Lab Code
LSHDNA
Epic Ordering
Leishmania Species DNA Detection
Description

Detection and identification of Leishmania species DNA.

Leishmaniasis is a fatal or disfiguring disease caused by a protozoan parasite transmitted by hematophagous sand flies. Globally, 350 million people are estimated to be at risk, resulting in ~1 million cases per year. There are two major forms of the disease: visceral leishmaniasis (VL), which is always treated, otherwise case fatality is ~80%; and cutaneous leishmaniasis (CL), for which the decision to treat is more complicated. The disease is an important diagnostic consideration in travelers from Latin America, the Middle East, North or East Africa, and has been reported in the Southern United States (1). Populations at risk include immunosuppressed persons, immigrants, military and foreign service personnel, and staff or volunteers from non-governmental organizations (1).

Given the toxicity of anti-leishmanial drugs, a confirmed laboratory diagnosis is required prior to starting therapy (2). The decision to treat CL depends upon clinical factors - patient immune status; number, size, duration, and anatomic location of lesions – and the species of parasite (2). While many cutaneous cases of “Old World” Leishmania spp (OWL) will be treated, small, isolated lesions of L. tropica may resolve spontaneously. Among “New World” Leishmania spp (NWL), the Viannia subgenus members have a propensity for mucocutaneous involvement (MCL) and dissemination and thus require treatment to prevent profound disfigurement.

Our Leishmania PCR assay offers highly sensitivity molecular identification of Leishmania spp that infect humans, with a limit of detection of a single organism per reaction. When Leishmania parasites are detected by the assay, sequencing identifies the causative organism to the species or species-complex. This test can be ordered as a stand-alone assay and is performed reflexively if broad-range fungal PCR detects Leishmania sp as an incidental finding.

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

References
  1. Curtin JM and Aronson NE. 2021. Leishmaniasis in the United States: Emerging Issues in a Region of Low Endemicity. Microorganisms. 9(3):578.
  2. Aronson N, Herwaldt BL, Libman M, Pearson R, Lopez-Velez R, Weina P, Carvalho E, Ephros M, Jeronimo S, Magill A. 2017. Diagnosis and Treatment of Leishmaniasis: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH). Am J Trop Med Hyg. 96:24–45.
Forms & Requisitions
Synonyms
Kinetoplast, Leishmania PCR, Leishmaniasis identification, Leishmaniasis PCR, Leishmaniasis sequencing, Leismania identification, Leismania sequencing, mini-exon PCR, parasite identification, protozoan identification
Components

Interpretation

Method

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

Reference Range
See individual components
References
  1. Curtin JM and Aronson NE. 2021. Leishmaniasis in the United States: Emerging Issues in a Region of Low Endemicity. Microorganisms. 9(3):578.
  2. Aronson N, Herwaldt BL, Libman M, Pearson R, Lopez-Velez R, Weina P, Carvalho E, Ephros M, Jeronimo S, Magill A. 2017. Diagnosis and Treatment of Leishmaniasis: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH). Am J Trop Med Hyg. 96:24–45.
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)
  • Sodium polyanethol sulfonate (SPS, Wampole Isolator Tubes) acceptable with disclaimer

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

Additional Acceptable Specimens

  • Buffy coat
  • Blood (only acceptable if stain positive)
  • Sputum

Unacceptable Specimens

  • Serum, plasma, stool
  • No citrated or heparinized solutions
  • Tissues floating in formalin
  • Swab/fluid collected in tube containing agar
Forms & Requisitions
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 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?
No

Billing & Coding

CPT codes
87801
LOINC
23159-7
Interfaced Order Code
UOW4248