MVista® PULMONARY FUNGAL PATHOGEN MULTIPLEX PCR PANEL

• Test Code

  1000

• CPT Code

  87798

• Clinical Significance

  Histoplasma capsulatum (also known as Ajellomyces capsulatum) is a dimorphic fungus which is the causative agent of Histoplasmosis, which primarily affects the lungs. Most infections are asymptomatic, but the acute phase may present with mild respiratory symptoms. Chronic histoplasmosis may progress to disseminated disease, which can be fatal, especially in immunocompromised individuals (e.g., HIV patients), though cases in healthy individuals have also been reported. Histoplasmosis is endemic to parts of the Americas, Asia, and Africa, but can occur elsewhere. The gold standard for diagnosis of histoplasmosis remains isolation of the organisms in culture. Although sensitive, recovery in culture and subsequent identification may require days to weeks. This polymerase chain reaction assay can provide rapid and specific detection and differentiation of Histoplasma capsulatum directly from clinical specimens. This real-time PCR assay provides 100% sensitivity and 100% specificity, with a limit of detection of 32 cells/mL for detection of Histoplasma from bronchoalveolar lavage (BAL) fluid.

  Blastomyces dermatitidis and Blastomyces gilchristii are dimorphic fungi which are the causative agents of Blastomycosis, which primarily affects the lungs. Most infections are asymptomatic, but the acute phase may present mild respiratory symptoms. Chronic blastomycosis may progress to disseminated disease, which can be fatal, especially in immunocompromised individuals (e.g., HIV patients), though cases in healthy individuals have also been reported. Blastomycosis is endemic to parts of the United States, Canada, Africa, the Middle East, and India, but can occur elsewhere. The gold standard for diagnosis of blastomycosis remains isolation of the organisms in culture. Although sensitive, recovery in culture and subsequent identification may require days to weeks. This polymerase chain reaction assay can provide rapid and specific detection and differentiation of Blastomyces dermatitidis and Blastomyces gilchristii directly from clinical specimens. This real-time PCR assay provides 96.67% sensitivity and 96.63% specificity, with a limit of detection of 6 cells/mL for detection of Blastomyces from bronchoalveolar lavage (BAL) fluid.

  Coccidioides immitis and Coccidioides posadasii are dimorphic fungi which are the causative agents of coccidioidomycosis (also known as Valley Fever), which primarily affects the lungs. Most infections are asymptomatic, but the acute phase may present as community acquired pneumonia (CAP). Chronic coccidioidomycosis may progress to disseminated disease, which can be fatal, especially in immunocompromised individuals (e.g., HIV patients), though cases in healthy individuals have also been reported. Coccidioidomycosis is endemic to the southwestern United States, as well as Washington, Mexico and Central America. The gold standard for diagnosis of coccidioidomycosis is enzyme immunoassay (EIA) antibody used in conjunction with an immunodiffusion (ID) or complement fixation (CF) antibody test. EIAs are known to cross react with other dimorphic fungi, resulting in a low-test specificity, while ID and CF tests lack sensitivity. This polymerase chain reaction assay can provide rapid and specific detection and differentiation of Coccidioides immitis and Coccidioides posadasii directly from clinical specimens. This real-time PCR assay provides 100% sensitivity and 100% specificity, with a limit of detection of 2.5 fg/mL for detection of Coccidioides from bronchoalveolar lavage (BAL) fluid.

  Pneumocystis jirovecii (formerly known as Pneumocystis carinii) is an opportunistic fungal pathogen that causes life-threatening Pneumocystis pneumonia (PCP) in immunocompromised patients, including those with HIV. Patients may present with non-specific symptoms such as fever, cough, shortness of breath, and fatigue. Pneumocystis cannot be cultured in vitro and has classically been diagnosed based upon clinical symptoms and radiographic findings with confirmation via microscopic visualization of stained organisms which has lower sensitivity that is reliant upon reader expertise. This real-time PCR assay provides 96.7% sensitivity and 100% specificity, with a limit of detection of 50 fg/mL for detection of Pneumocystis from bronchoalveolar lavage (BAL) fluid.

  Multiplex PCR allows for the simultaneous detection of multiple fungal pathogens from a single sample. This is especially valuable in patients presenting with non-specific respiratory symptoms or community-acquired pneumonia, where fungal infections may mimic bacterial or viral causes. These fungi (Histoplasma, Blastomyces, Coccidioides, and Pneumocystis) are common causes of opportunistic infections, particularly in HIV-positive or immunocompromised individuals. Early and accurate identification can significantly improve outcomes. In addition, patients may have co-infections with more than one fungal pathogen and multiplex PCR can identify these cases, allowing for more comprehensive treatment planning.

• Methodology

  Qualitative Real-Time PCR (Polymerase Chain Reaction)

• Limitations

  403 MVista® Histoplasma DNA, PCR: When tested in cultures of 108 – 109 organisms/mL, cross-reactions occurred with Paracoccidioides brasiliensis, Aspergillus flavus, Aspergillus nidulans, and Aspergillus niger.

  404 MVista® Blastomyces DNA, PCR: When tested in cultures of 108 – 109 organisms/mL, cross-reactions occurred with Cryptococcus neoformans.

• Specimen Collection

  Transfer 2 mL of bronchoalveolar lavage (BAL) fluid to a sterile, leakproof container. Tracheal aspirate and bronchial wash will be reported with a rare specimen comment.

• Minimum Specimen Requirements

  0.5mL bronchoalveolar lavage (BAL) fluid

• Specimen Stability
  • Room Temperature/Ambient: 30 days
  • Refrigerated: 30 days
  • Frozen: 30 days
• Specimen Rejection
  • Sputum and all other non-respiratory samples.
  • Two unique patient identifiers are required on the specimen container.
  • Specimens with particulate matter or viscosity that would not allow the specimen to be pipetted will be rejected.
• Turnaround Time

  24-48 hours, Monday through Friday

• Reference Range

  Not detected

• Interpretative Information

  PCR testing should be done in conjunction with appropriate antigen or antibody testing. A positive PCR result indicates the DNA was detected in the sample and that organism could be the cause of disease. Some organisms (molds and yeasts) can be commensals (or colonizers) and found in non-sterile locations such as the respiratory, GI, and urinary systems – without causing disease. A negative result indicates DNA was not detected in the sample but does not rule-out that organism as the cause of disease. All results should be interpreted considering the full clinical picture.

• Additional Information

  This test was developed, and its analytical performance characteristics were determined by MiraVista Diagnostics. It has not been cleared or approved by the FDA; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

• Panel Components
  • 402 MVista® Pneumocystis DNA, PCR
  • 403 MVista® Histoplasma DNA, PCR
  • 404 MVista® Blastomyces DNA, PCR
  • 405 MVista® Coccidioides DNA, PCR
• Accepted Specimen Types
  • Bronchoalveolar Lavage (BAL)