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Test Code TWRP Tropheryma whipplei, Molecular Detection, PCR, Varies

Reporting Name

Tropheryma whipplei PCR

Useful For

Aiding in the diagnosis of Whipple disease, especially for identifying inconclusive or suspicious cases, using tissue or fluid specimens

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Varies


Necessary Information


Specimen source is required.



Specimen Required


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

 

Submit only 1 of the following specimens:

 

Specimen Type: Fresh tissue or biopsy

Sources: Small intestine (duodenum, ileum, or jejunum), lymph node, bone, joint, synovial, liver, pancreas, spleen, lung, heart valve (and other heart tissues), or brain

Container/Tube: Sterile container

Specimen Volume: Entire collection or 5 mm(3) - approximately the size of a pencil eraser

Collection Instructions:

1. Collect fresh tissue specimen.

2. Submit tissue only, do not add fluid to tissue.

3. Refrigerate or freeze specimen.

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

 

Preferred Paraffin-embedded tissue block:

Supplies: Tissue Block Container (T553)

Specimen Type: Formalin-fixed, paraffin-embedded tissue block (FFPE)

Sources: Small intestine (duodenum, ileum, or jejunum), lymph node, bone, joint, synovial, liver, pancreas, spleen, lung, heart valve (and other heart tissues), or brain

Container/Tube: Tissue block

Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block to be cut and returned.

Specimen Stability Information: Ambient (preferred)/Refrigerated

 

Acceptable Paraffin-embedded tissue block:

Specimen Type: Formalin-fixed, paraffin-embedded tissue block (FFPE)

Sources: Small intestine (duodenum, ileum, or jejunum), lymph node, bone, joint, synovial, liver, pancreas, spleen, lung, heart valve (and other heart tissues), or brain

Container/Tube: Sterile container for each individual cut section (scroll).

Collection Instructions: Perform microtomy and prepare five separate 10-micron sections. Each section (scroll) must be placed in a separate sterile container for submission.

Specimen Stability Information: Ambient (preferred)/Refrigerated

 

Specimen Type: Fluid

Sources: Cerebrospinal or ocular (eg, vitreous humor)

Container/Tube: Sterile vial

Specimen Volume: 0.5 mL

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

 

Specimen Type: Synovial fluid

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Pink top (EDTA), royal blue top (EDTA), sterile vial containing EDTA-derived aliquot, red clot tube (no anticoagulant), or sterile container

Specimen Volume: 0.5 mL

Collection Instructions: Send specimen in original tube (preferred).

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


Specimen Minimum Volume

Fluid: 0.5 mL
Fresh tissue or biopsy: 5 mm(3)
Paraffin-embedded tissue block: two 10-micron sections

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reference Values

Not applicable

Day(s) Performed

Monday through Friday

Test Classification

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

CPT Code Information

87798

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TWRP Tropheryma whipplei PCR 97206-7

 

Result ID Test Result Name Result LOINC Value
SRC56 Specimen source 31208-2
22302 Tropheryma whipplei PCR, Result 97206-7

Clinical Information

Whipple disease is a chronic, systemic illness that, in most cases, involves the small intestine and its lymphatic drainage. The disease primarily affects adults of middle age, 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. Molecular techniques using polymerase chain reaction 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.

Interpretation

A positive result indicates the presence of Tropheryma whipplei DNA.

 

A negative result indicates the absence of detectable T whipplei DNA but does not negate the presence of the organism and may occur due to inhibition of polymerase chain reaction, sequence variability underlying primers or probes, or the presence of T whipplei DNA in quantities less than the limit of detection of the assay.

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.

Report Available

2 to 7 days

Reject Due To

Slides
Bone marrow		 Reject

Method Name

Real-Time Polymerase Chain Reaction (PCR)

Forms

If not ordering electronically, complete, print, and send a  Gastroenterology and Hepatology Test Request (T728) with the specimen.