Background: Urine is traditionally considered as the gold-standard sample for the detection of congenital cytomegalovirus (CMV) infection. Although universal neonatal screening has been suggested as means for timely identification and treatment, overall, this approach has not been practically implemented, partially due to the difficulties in obtaining fresh urine samples from newborns. Recently, the clinical utility of saliva real time (RT)-PCR has been suggested in universal screening studies.
Objective: To determine the efficiency of saliva RT-PCR versus urine culture in the targeted screening of neonates at risk for having congenital CMV infection and validate an efficient screening algorithm.
Methods: Between 01/2014 and 06/2015, 633 pairs of urine and saliva samples, obtained within the first 10 days of life from clinically-suspected neonates, were prospectively examined for CMV infection by RT-PCR in saliva and urine culture. Discordant results were further examined by urine RT-PCR. Included were neonates with suspected maternal infection during pregnancy, intra uterine growth restriction, thrombocytopenia, and failure in neonatal hearing screening.
Results: Of 633 urine-saliva pairs examined, 51(8.1%, 95%CI±2.1%, 5.6%-10.2%) were positive by saliva RT-PCR and 26 (4.1%, 95%CI±1.5%, 2.6%-5.6%) were positive by urine culture. The calculated measures for saliva efficiency in the studied population were: sensitivity, 96.2% (25/26), specificity, 95.7% (581/607), positive predictive value (PPV), 49.0% (25/51), and negative predictive value (NPV) 99.8% (581/582).
Conclusions: Saliva RT-PCR assay is a highly sensitive and feasible method for targeted screening of clinically-suspected neonates. A diagnostic algorithm based on initial saliva RT-PCR screening with subsequent confirmation of positive results by urine testing was consequently instituted.
