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Pneumocystis pneumonia is an important cause of opportunistic infection in immunocompromised patients, particularly those with HIV. The causative agent, Pneumocystis jiroveci, cannot be cultured in vitro and, therefore, laboratory detection has historically relied upon microscopic identification directly from patient specimens using fluorescent stains or antibodies. Unfortunately, stains often lack sensitivity and require expertise on the part of the reader in order to differentiate Pneumocystis jiroveci from staining artifacts and other fungi. This real-time PCR assay provides sensitive (21% more sensitive than direct detection using fluorescent calcofluor white stain), specific, and objective detection of Pneumocystis from bronchoalveolar lavage fluid and other specimens.
Preferred test for detection of Pneumocystis
A positive result indicates the presence of Pneumocystis DNA.
A negative result indicates the absence of detectable Pneumocystis DNA.
Test results should be used as an aid in diagnosis and should not be considered diagnostic in themselves. The literature indicates that Pneumocystis can cause asymptomatic colonization of healthy and immunocompromised individuals. Therefore, test results should be correlated with patient symptoms and clinical presentation.
A negative result does not rule out the presence of Pneumocystis or active disease because the organism may be present at undetectable levels.
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