Pooled saliva CMV DNA detection: A viable laboratory technique for universal CMV screening of healthy newborns

Most infants with congenital cytomegalovirus (cCMV) have no overt manifestations at birth, yet may later develop CMV-related sensorineural hearing loss (SNHL). With targeted screening, many asymptomatic neonates are missed and lose the opportunity for timely anti-viral treatment to ameliorate SNHL. Saliva is the preferred screening specimen given its ease of collection.

Assess a pooled saliva CMV DNA detection technique for cCMV screening of healthy full-term neonates.

We conducted a prospective laboratory CMV PCR screening study in a secondary hospital from March-June 2019. Saliva specimens were obtained from 1000 newborns two-four hours after birth. Specimens were analyzed for CMV DNA with a real-time PCR platform (Altona) in pools of 10 and individually (40 μL and 400 μL, respectively). Neonates with positive saliva CMV DNA detection required urine CMV PCR testing to confirm cCMV diagnosis.

From the 1000 saliva samples, there were 6 urine-confirmed cCMV cases, yielding a prevalence rate of 0.6 %. The specificity was high for both pooled and individual saliva sampling (99.9 % and 98.1 %, respectively). The positive predictive value of the pooled sample was 85.7 %, compared to 24.0 % for a single saliva sample.

Pooling saliva of healthy newborns appears to be a reliable method to identify asymptomatic cCMV infection when positive results are confirmed by urine CMV DNA. Pooling in sizes appropriate to the cCMV prevalence rate may improve the laboratory workflow and decrease costs. Further studies should evaluate the clinical implications of this widespread cCMV pooled screening technique.