Tropheryma whipplei DNA detection by PCR
General Information
- Lab Name
- Tropheryma whipplei DNA detection by PCR
- Lab Code
- TWHDNA
- Epic Ordering
- Tropheryma whipplei DNA detection by PCR
- Description
Detection of Tropheryma whipplei DNA.
Whipple's disease is an infectious illness associated with a wide variety of intestinal and extraintestinal manifestations. Since untreated disease leads to death and because adequate antimicrobial therapy for diseases with similar clinical presentations differs significantly in the duration and choice of drugs, a reliable laboratory diagnosis is of considerable interest. The causative agent has been propagated in human macrophages deactivated with interleukin-4, but stable subcultures have been established only very recently. Based on its 16S ribosomal DNA (rDNA) sequence, it was classified as a member of the gram-positive bacteria with high G+C content and named Tropheryma whipplei (formerly Tropheryma whippelii).Recently, T. whipplei DNA has been found in duodenal biopsy tissue, gastric juice, and saliva specimens, but not in dental stone, of patients without Whipple's disease.
Despite recent success in culturing T. whipplei, the clinical suspicion of Whipple's disease is usually confirmed by periodic acid-Schiff staining of inclusions in macrophages or by electron microscopy showing the characteristic trilamellar membrane of T. whipplei.
Molecular tests are significantly more sensitive than histopathology for intestinal and extraintestinal specimens. T. whipplei-specific seminested PCR utilizes a 500-bp segment of the hsp65 gene for the specific detection of T. whipplei.
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
La Scola et al. 51 (4):(2001) Description of Tropheryma whipplei gen. nov., sp. nov., the Whipple’s disease bacillus in International Journal of Systematic and Evolutionary Microbiology, pp1471–1479
- Synonyms
- 16S PCR, molecular Tropheryma whipplei, Tropheryma whipplei identification, Tropheryma whipplei PCR, Tropheryma whipplei sequencing, Twhip PCR, universal PCR, Whipple’s disease, Whipple’s PCR
- Components
-
Interpretation
- Method
DNA extraction, nucleic acid purification, polymerase chain reaction (PCR), sequencing
- Reference Range
- See individual components
- References
La Scola et al. 51 (4):(2001) Description of Tropheryma whipplei gen. nov., sp. nov., the Whipple’s disease bacillus in International Journal of Systematic and Evolutionary Microbiology, pp1471–1479
- 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
- Saliva
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
206-520-4600Clinical 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
- 87798
- LOINC
- 46725-8
- Interfaced Order Code
- UOW4382