Pooled Saliva CMV PCR: A Viable Laboratory Technique for Universal CMV Screening of Healthy Newborns

Background: Most congenital CMV (cCMV) infected infants have no overt manifestations at birth; still, CMV-related sensorineural hearing loss (SNHL) may be present. Valganciclovir has the potential to ameliorate long-term hearing outcome, yet with targeted screening, many neonates with SNHL are missed. Saliva is recommended as the preferred screening specimen. Accordingly, we investigated the screening of healthy full-term neonates employing a pooled saliva specimen technique.

Materials/methods: We conducted a prospective universal CMV PCR screening study of neonates in an Israeli hospital. Saliva specimens extracted in pools of 10 and individually (40μL and 400 μL, respectively) were analyzed for the presence of CMV DNA employing a real-time platform (Qiagen). Positive pooled specimens were evaluated to determine the source(s) of CMV. A definitive cCMV was defined only after confirmation of positive urine.

Results: Of the 1000 saliva samples, there were 6 urine-confirmed congenital CMV patients attained by both laboratory techniques. The specificity of both techniques was high with the pooled specimen yielding 98.94 (95% CI: 94.2-99.97%) and the individual sampling 98.1% (95% CI: 97.0-98.8%), respectively. False positive results were significantly higher in individual than in pooled sampling, 19/25 (76.0%) versus 1/7 (14.3%), p<.003, respectively.

Conclusions: Pooled saliva CMV PCR of healthy newborns appears to be an effective technique for the identification of asymptomatic cCMV infection. Pooled specimens afford a higher specificity by decreasing the rate of saliva false-positive samples and may have the potential to improve laboratory workflow. Further studies are needed to evaluate the clinical correlation of this widespsread cCMV screening technique.