Home
HelpTest Code WHIPB Tropheryma whipplei, Molecular Detection, PCR, Blood
Reporting Name
Tropheryma whipplei PCR, BUseful For
Aiding in the diagnosis of Whipple disease, especially for identifying inconclusive or suspicious cases, using whole blood specimens
Testing Algorithm
For more information see Infective Endocarditis: Diagnostic Testing for Identification of Microbiological Etiology
Method Name
Real-Time Polymerase Chain Reaction (PCR)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Whole Blood EDTASpecimen 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.
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Royal blue top (EDTA), pink top (EDTA), or sterile vial containing EDTA-derived aliquot
Specimen Volume: 1 mL
Collection Instructions: Send whole blood specimen in original tube (preferred)
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Refrigerated (preferred) | 7 days | |
| Ambient | 7 days | ||
| Frozen | 7 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Special Instructions
Reference Values
Not applicable
Day(s) Performed
Monday through Friday
CPT Code Information
87798
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| WHIPB | Tropheryma whipplei PCR, B | 97205-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| SRC89 | Specimen Source | 31208-2 |
| 56064 | Tropheryma whipplei PCR, B, Result | 97205-9 |
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 adults of middle age, with a peak incidence in the third and fourth decades of life. 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 allow 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 it 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.
Method Description
Nucleic acid is extracted from all specimens using the MagNA Pure extraction system. The resulting nucleic acid is tested for the presence of the target DNA of Tropheryma whipplei using the LightCycler real-time polymerase chain reaction (PCR). The instrument amplifies and continuously monitors the development of target nucleic acid using fluorescent resonance emission technology after each cycle. Analysis of the PCR amplification and probe melting curves is accomplished through the use of the LightCycler software.(Sloan LM, Rosenblatt JE, Cockerill FR III: Detection of Tropheryma whipplei DNA in clinical specimens by LightCycler real-time PCR. J Clin Microobiol. 2005;43:3516-3518; Geibdorfer W, Moter A, Bogdan C: Tropheryma whipplei, In: Carroll K, Pfaller M, eds. Manual of Clinical Microbiology. 12th ed. ASM Press; 2019:1189-1197)