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Test ID TWRP Tropheryma whipplei, Molecular Detection, PCR

Useful For

An aid in diagnosis of Whipple disease, especially for identifying inconclusive or suspicious cases

Method Name

Rapid Polymerase Chain Reaction (PCR)

(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)

Reporting Name

Tropheryma whipplei PCR

Specimen Type

Varies

The high sensitivity of amplification by PCR requires the specimen to be processed in an environment in which contamination of the specimen by Tropheryma whipplei DNA is unlikely.

 

Forms: If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

Microbiology Test Request Form (T244) (http://www.mayomedicallaboratories.com/it-mmfiles/microbiology_test_request_form.pdf)

Neurology Test Request Form-General (T732) (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)

 

Submit only 1 of the following specimens:

 

Specimen Type: Fresh tissue or biopsy

Sources: Small intestine tissue (duodenum, ileum, or jejunum), lymph node, other visceral tissue, synovial tissue, gastrointestinal tissue, heart valve, or brain

Container/Tube: Sterile container

Specimen Volume: Entire collection or 5 mm(3)

Collection Instructions: Collect fresh tissue specimen

Specimen Stability Information: Refrigerated <7 days (preferred)/Frozen <7 days

 

Specimen Type: Paraffin-embedded tissue block

Sources: Small intestine tissue (duodenum, ileum, or jejunum), lymph node, other visceral tissue, synovial tissue, gastrointestinal tissue, heart valve, or brain

Container/Tube: Sterile vial

Collection Instructions: Submit formalin-fixed, paraffin-embedded tissue block to be cut and returned; or two to five 10-micron sections in a sterile container

Specimen Stability Information: Ambient (preferred)/Refrigerated

 

Specimen Type: Fluid

Sources: Cerebrospinal, synovial, or vitreous humor

Container/Tube: Sterile vial

Specimen Volume: 0.5 mL

Specimen Stability Information: Refrigerated <7 days (preferred)/Frozen <7 days

Specimen Minimum Volume

Spinal Fluid, Synovial Fluid, or Vitreous Humor Fluid: 0.5 mL/Tissue: 5 mm(3) or two 10-micron sections

Specimen Stability Information

Specimen Type Temperature Time
Varies Varies

Clinical Information

Whipple disease is a chronic, systemic illness that in the majority of cases involves the small intestine and its lymphatic drainage. The disease primarily affects middle-aged individuals, with a peak incidence in the third and fourth decades. Clinical findings may include malabsorption, chronic diarrhea, abdominal pain, arthralgia, fever, and central nervous system symptoms.

 

Pathologic changes associated with Whipple disease are distinctive, with diagnosis dependent on histologic examination of biopsy specimens from involved tissues. Electron microscopic or special high-resolution light microscopic examination of the lamina propria of the small intestine of patients with untreated Whipple disease reveals many rod-shaped bacillary organisms. These tiny bacilli, referred to as Whipple bacilli, measure about 0.25 micrometer long and are seen as periodic acid-Schiff-positive granules within macrophages. These inclusions represent fragments of the cell walls from degenerating bacilli.

 

Culture of Whipple bacilli from biopsy material is laborious and the organism is very slow growing. Definitive identification of the Whipple associated bacillus has been difficult because of these limitations. Recently, molecular techniques using PCR and nucleotide sequencing allowed classification of this bacillus as an actinomycete not closely related to any other known species, which has been named Tropheryma whipplei.

Reference Values

Not applicable

Cautions

Test results should be used as an aid in diagnosis and not be considered diagnostic in themselves. The single assay should not be used as the only criteria to form a clinical conclusion, but results should be correlated with patient symptoms and clinical presentation. A negative result does not negate the presence of the organism or active disease.

Day(s) Performed

Monday, Wednesday, Friday

Report Available

2 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

87798

NY State Approved

Yes