Nasopharyngeal viral PCR in immunosuppressed patients and its association with virus detection in bronchoalveolar lavage by PCR

Background and objectivePulmonary infiltrates are common in immunosuppressed patients. Bronchoscopy with bronchoalveolar lavage (BAL) is often used to evaluate their aetiology. However, it may not always be easily performed. Thus, alternative diagnostic strategies may be needed. There is limited data on the correlation of nasopharyngeal (NP) respiratory viral panel (RVP)-PCR testing compared with BAL. We aimed to identify the predictive value of NP RVP-PCR samples compared with samples obtained from BAL in immunosuppressed patients with pulmonary infiltrates. MethodsWe conducted an observational retrospective study of immunosuppressed adults who underwent bronchoscopy in the Pulmonary Department at the University of Rochester Medical Center between January 2011 and June 2016. We compared the positive and negative predictive values, sensitivity, specificity and false negative rate of NP RVP-PCR and BAL RVP-PCR, as well as identified clinical predictors of positive viral BAL RVP-PCR. ResultsEighty-nine immunosuppressed patients had both NP and bronchoalveolar RVP-PCR testing. Twenty-one patients had NP(+)BAL(+) RVP-PCR testing. Seven patients had false negative (NP(-)BAL(+)) RVP-PCR testing. Three patients had NP(+)BAL(-) RVP-PCR testing. The positive and negative predictive values of NP RVP-PCR testing were 88% and 89%, respectively. Allogeneic bone marrow transplantation and testing performed in the winter and spring months were significantly associated with positive BAL RVP-PCR (OR=3.3 (1.19-9.12); OR=4.62 (1.64-12.99), respectively). Conclusion NP RVP-PCR testing has high concordance with testing performed on BAL samples. Repeat testing through BAL is beneficial when there is high concern for viral infection after initial NP RVP-PCR testing is negative. There are limited data on nasopharyngeal (NP) testing compared with bronchoscopy in immunosuppressed patients. NP PCR testing has a false negative rate of 8%, positive predictive value of 88% and negative predictive value of 89%.