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Comparative Study
. 2020 May 1;13(1):235.
doi: 10.1186/s13104-020-05075-5.

Is real time PCR preferable to the direct immunofluorescence in the diagnosis of Pneumocystis jirovecii pneumonia in HIV-infected patients?

Simon Bossart  1   2 , Konrad Mühlethaler  3 , Christian Garzoni  4   5 , Hansjakob Furrer  4
Affiliations
Comparative Study

Is real time PCR preferable to the direct immunofluorescence in the diagnosis of Pneumocystis jirovecii pneumonia in HIV-infected patients?

Simon Bossart et al. BMC Res Notes. .

Abstract

Objectives: In this study, we compared IFA and real-time PCR in bronchoalveolar lavage specimens of HIV infected patients. A total of 66 BALs from 62 HIV patients were included in the study. 30 IFA positive and 36 IFA negative specimens were tested with real-time PCR, targeting the major surface glycoprotein. We performed a retrospective analysis of the patient's medical records, compared the results of the IFA and PCR tests and analyzed costs, expenditure of time and personal expenses.

Results: All of the 30 IFA positive samples were PCR positive. 35 of 36 IFA negative probes were also negative in the PCR assay. Considering the PCR results as a binary outcome (positive/negative) sensitivity was 100%, specificity 97.2%. The patient with negative IFA and positive PCR had a clear clinical picture of PCP and responded to PCP treatment. PCR was more than twice as expensive and time-consuming as IFA. Diagnostic accuracy for PCP of PCR and IFA was comparable in HIV-infected patients, but IFA was significantly less expensive and less time-consuming. Therefore, IFA testing can continue to be used as gold standard in the diagnosis of PCP in HIV patients. However, in special cases, IFA may lack sensitivity and PCR should be added to the diagnostic armamentarium.

Keywords: HIV; Immunofluorescence assay; Pneumocystis jirovecii; Pneumocystis pneumonia; Real-time PCR.

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Conflict of interest statement

All authors declare that they have no significant competing financial, professional, or personal interests that might have influenced the performance or presentation of the work described in this manuscript.

Figures

Fig. 1
Fig. 1
Comparison between IFA (number of asci or trophic forms per field of vision) and PCR (copies/ml) of all tested BAL samples. One specimen with a discrepant result with negative IFA and positive low copies PCR (297 copies/ml) showed in the red circle
See this image and copyright information in PMC

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