Saliva vs. Urine PCR: The Ideal Sample for congenital CMV Screening and Diagnosis
Methods: As part of the NIDCD CHIMES study, newborns at 7 U.S. medical centers were screened for CMV by saliva and dried blood spot PCR. Infants who screened positive were enrolled in a follow-up study to confirm congenital infection by testing saliva and urine samples using a previously described real-time PCR assay. CMV viral load in saliva samples obtained at screening and enrollment was compared to urine collected at enrollment in follow-up.
Results: Of the 100,332 newborns screened for CMV from 2007 to 2011, viral load levels in both saliva and urine samples were available in 73% (336/462) of infants with confirmed cCMV. Of these, 36% (121/336) were enrolled within the first 3 weeks of life. The median viral load level in saliva at screening and enrollment (2.x106 IU/ml and 1.1x107 IU/ml, respectively) was significantly higher than in urine (8.3x105 IU/ml; p < 0.0001). There was no significant difference between VL in saliva and urine in infants with and without symptomatic disease and with and without congenital SNHL. In the smaller cohort of infants enrolled within 3 weeks of birth, median saliva VL at screening and enrollment (1.1x106 IU/ml vs. 9.3x106 IU/ml, respectively) was higher than urine VL (7.9x105IU/ml; p < 0.0001) .
Conclusion: Infants with congenital CMV infection shed large amounts of virus in both saliva and urine. However, saliva samples contained higher viral load than urine, are easier to collect and do not require DNA extraction. Therefore, we propose that saliva should be considered the ideal specimen and real-time PCR of saliva is appropriate for both newborn screening and diagnosis of cCMV.
S. G. Pinninti,
Z. Novak, None
A. Palmer, None
A. Ahmed, None
P. J. Sanchez, None
M. Michaels, None
D. Bernstein, Genocea: Research Contractor, Research support
K. N. Feja, None
A. Stewart, None
K. Fowler, None
S. Boppana, None