Poor positive predictive value of influenza-like illness criteria in adult transplant patients: a case for multiplex respiratory virus PCR testing.

Abstract

BackgroundRespiratory viral infections (RVIs) are a significant cause of morbidity and mortality among transplant patients. The CDC's influenza‐like illness (ILI) criteria (fever ≥100°F with cough and/or sore throat) are a screening tool for influenza with unknown applicability to the transplant population.MethodsWe reviewed all respiratory virus PCR tests performed on adult patients with a history of solid organ (SOT) or stem cell transplantation (HSCT) during the 2012–2013 influenza season. The positive (PPV) and negative predictive values (NPV) of ILI criteria were calculated.ResultsOf 126 transplant patients (66 HSCT, 60 SOT), 54 (42.8%) tested positive for an RVI by PCR: 24 influenza and 30 non‐influenza. Of 30 patients who met ILI criteria, 12 (40%) were positive for influenza. The PPV and NPV of ILI for influenza were 50% and 82.4%, respectively. Mortality was low (3.7%), but morbidity was high (14.8% required ICU stay) among transplant patients diagnosed with RVI.ConclusionsInfluenza and non‐influenza RVIs are associated with significant morbidity among transplant patients. CDC ILI criteria correlate poorly with PCR‐positive cases of influenza in transplant patients, but may be useful in excluding the diagnosis. Routine RVI PCR testing is recommended for better diagnosis and improved antiviral use in transplant patients with suspected RVI.