Microbiological Laboratory Testing in the Diagnosis of Fungal Infections in Pulmonary and Critical Care Practice. An Official American Thoracic Society Clinical Practice Guideline

Abstract

Background: Fungal infections are of increasing incidence and importance in immunocompromised and immunocompetent patients. Timely diagnosis relies on appropriate use of laboratory testing in susceptible patients. Methods: The relevant literature related to diagnosis of invasive pulmonary aspergillosis, invasive candidiasis, and the common endemic mycoses was systematically reviewed. Meta-analysis was performed when appropriate. Recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation approach. Results: This guideline includes specific recommendations on the use of galactomannan testing in serum and BAL and for the diagnosis of invasive pulmonary aspergillosis, the role of PCR in the diagnosis of invasive pulmonary aspergillosis, the role of β- d -glucan assays in the diagnosis of invasive candidiasis, and the application of serology and antigen testing in the diagnosis of the endemic mycoses. Conclusions: Rapid, accurate diagnosis of fungal infections relies on appropriate application of laboratory testing, including antigen testing, serological testing, and PCR-based assays.

Review of influenza-associated pulmonary aspergillosis in ICU patients and proposal for a case definition: an expert opinion

“…A BAL GM index cutoff of ≥ 1.0 is recommended as this cutoff value ensures high specificity, without decreasing sensitivity significantly, which is also in line with other definitions and recommendations [10,57]. Aspergillus PCR is not recommended as a primary diagnostic tool because of concerns about its reliability and positive predictive value for the diagnosis of IPA.…”

Diagnosis of severe respiratory infections in immunocompromised patients

“…Invasive fungal infections (IFI) are classified as proven (signs of infection and fungus identified by histopathology, cytopathology, or culture), probable (based on host factors, clinical criteria, microscopy, culture, galactomannan antigen [GM], or possible (based on host factors and clinical criteria) [88]. The diagnosis of P. jirovecii pneumonia (PJP) relies on identification of the pathogen by immunofluorescence and quantitative PCR (on BAL fluid ideally and induced sputum otherwise); serum BDG testing can be helpful for difficult cases where there is a discrepancy between the clinical picture and PCR findings, or to make the difference between colonization and infection when PCR findings are in the gray zone [85].…”

“…1). PCR and GM testing may perform better on BAL fluid than on serum, although FOB/BAL should be done only if indicated by a careful risk/benefit assessment [88]. Serum BDG testing is recommended in highrisk patients, but is not specific for IA.…”

Bronchoalveolar lavage to evaluate new pulmonary infiltrates in allogeneic hematopoietic stem cell transplant recipients: impact on antimicrobial optimization

“…At a cutoff of 1.5, sensitivity reduces to 59% and specificity increases to 95%. For BAL AGA with a cutoff of 1.0, the sensitivity and specificity increases to 90% and 94% respectively [9]. In addition, Aspergillus spp.…”