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HelpTest Code CBRP Coxiella burnetii (Q fever), Molecular Detection, PCR, Varies
Reporting Name
Coxiella burnetii (Q fever) PCRUseful For
Aiding in the diagnosis of Coxiella burnetii infection (eg, Q fever) using tissue specimens
Testing Algorithm
For more information see Infective Endocarditis: Diagnostic Testing for Identification of Microbiological Etiology
Method Name
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
VariesNecessary 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 Coxiella burnetii DNA is unlikely.
Submit only 1 of the following specimens:
Specimen Type: Fresh tissue or biopsy
Sources: Lung, bone, liver, heart valve, aorta, or endocardium
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:
Specimen Type: Formalin-fixed, paraffin-embedded tissue block (FFPE)
Sources: Lung, bone, liver, heart valve, aorta, or endocardium
Supplies: Tissue Block Container (T553)
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: Lung, bone, liver, heart valve, aorta, or endocardium
Container/Tube: Sterile container for each individual cut section (scroll).
Collection Instructions: Perform microtomy and prepare 5 separate 10-micron sections. Each section (scroll) must be placed in a separate sterile container for submission.
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Minimum Volume
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 | ||
Reject Due To
| Â Tissue in formalin formaldehyde, or acetone Bone marrow Decalcified bone Unstained slides |
Reject |
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 |
|---|---|---|
| CBRP | Coxiella burnetii (Q fever) PCR | 90442-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| SRCQF | Specimen Source | 31208-2 |
| 62193 | Coxiella burnetii PCR | 90442-5 |
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.Clinical Information
Coxiella burnetii, the causative agent of Q fever, is a small obligate intracellular bacterium associated with animals. Acquired through aerosol exposure, it generally causes mild respiratory disease. A small number of acute cases advance to a chronic infection, which typically manifests as endocarditis. Left untreated, Q fever endocarditis may be fatal. Serologic and histopathologic studies may be nonspecific and subjective, respectively, limiting usefulness for patient diagnosis.
Evaluation of infected tissue, blood, or serum using polymerase chain reaction (PCR) may be a useful tool for diagnosing some cases of C burnetii infection. Mayo Clinic Laboratories has developed a real-time PCR test that rapidly detects C burnetii DNA in clinical specimens by targeting a sequence of the shikimate dehydrogenase gene (aroE) unique to C burnetii.
Interpretation
A positive result indicates the presence of Coxiella burnetii DNA.
A negative result indicates the absence of detectable C burnetii 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 C burnetii 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. A 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.
Supportive Data
This assay was clinically validated in a blinded manner using 52 archived, formalin-fixed, paraffin-embedded heart valve specimens from patients with endocarditis. A single sample determined to contain polymerase chain reaction (PCR) inhibitors was omitted from the final analysis set. Compared with existing diagnostic data, PCR had a sensitivity of 100% (8/8) and specificity of 100% (43/43). All samples were assayed with a second PCR assay targeting the IS1111 element.(1) Complete concordance was noted between the 2 assays (P >0.999). The limit of detection of the assay is 216 targets/mcL for fresh tissue and estimated (by Probit analysis) to be 9.7 targets/mcL in formalin-fixed paraffin-embedded tissue.
Method Description
Bacterial nucleic acid is extracted from the specimen using the automated MagNA Pure instrument. The purified DNA is placed on the LightCycler instrument, which amplifies and monitors by fluorescence the development of target nucleic sequences after each PCR cycle. A specific target sequence from Coxiella burnetii is amplified and the resulting segment is detected using specific hybridization probes. Detection of the C burnetii target is performed through melting curve analysis using the LightCycler software.(Cockerill FR, Uhl FR: Applications and challenges of real-time PCR for the clinical microbiology laboratory. In: Reischl U, Wittwer C, Cockerill F, eds. Rapid Cycle Real-Time PCR, 2002:3-27; Kersh GJ, Bleeker-Rovers CP: Coxiella. In: Carroll K, Pfaller M, eds. Manual of Clinical Microbiology. 12th ed. ASM Press; 2019:1180-1188)
Report Available
2 to 7 daysSpecimen Retention Time
7 daysForms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.