Delayed RSV diagnosis in a stem cell transplant population due to mutations that result in negative polymerase chain reaction.

Respiratory syncytial virus (RSV) is a serious cause of morbidity and mortality in the adult hematopoietic stem cell transplant (HSCT) population. The timely diagnosis of RSV infection in this population is important for initiating therapy and instituting appropriate infection prevention measures. Molecular multiplex assays now offer increased sensitivity for a more accurate diagnosis. This study presents 5 cases of RSV infection in HSCT patients in which diagnosis was delayed due to false-negative results from a multiplex polymerase chain reaction (PCR) assay. The false-negative result was due to a single base-pair mutation in the RSV strain. These false results delayed the appropriate treatment of patients. This study shows that a combination of a multiplex PCR assay, viral antigen, and/or culture should be used to detect variants of RSV in patients and that multiplex respiratory viral assays should develop a more robust design that includes multiple genetic target per virus to prevent missing viruses that continue to have genetic variances.