Clinical Use of Fungal PCR from Deep Tissue Samples in the Diagnosis of Invasive Fungal Diseases - A Retrospective, Observational Study.

We evaluated the clinical use of panfungal polymerase chain reaction (PCR) for diagnosis of invasive fungal diseases (IFDs). We focused on the deep tissue samples.We first described the design of panfungal PCR, which is in clinical use at Helsinki University Hospital. Secondly, we retrospectively evaluated the results of 307 fungal PCR tests performed from 2013-2015. Samples were taken from normally sterile tissues and fluids. The patient population was non-selected. We classified the likelihood of IFD according to the criteria of the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG), compering the fungal PCR results to the likelihood of IFD along with the culture and microscopy results.There were 48 (16%) positive and 259 (84%) negative PCR results. The sensitivity and specificity of PCR for diagnosing invasive fungal disease were 60.5% and 91.7%, respectively, while the NPV and PPV were 93.4% and 54.2%, respectively. The concordance between the PCR and the culture results was 86% and 87% between PCR and microscopy, respectively. Of the 48 patients with positive PCR results 23 had a proven or probable IFD.Fungal PCR can be useful for diagnosing IFDs in deep tissue samples. It is beneficial to combine fungal PCR with culture and microscopy.