Dried blood spot screening detects congenital CMV

The prevalence of congenital cytomegalovirus (CMV) determined by testing dried blood spots for the presence of CMV DNA is similar to the prevalence reported on the basis of standard viral cultures, according to a recent report. Investigators examined 3,972 newborn dried blood spots for the presence of CMV DNA. Congenital CMV prevalence among all infants in the study population was 0.7%; it was highest among infants born to black mothers (0.9%), followed by Hispanics (0.8%), whites (0.6%), and Asians (0.6%).

Congenital CMV prevalence was higher among infants with no father information on the live-birth record than among infants with father information. Among Hispanics, mothers of infected infants were younger than mothers of noninfected infants, and congenital CMV prevalence rates generally decreased with increased maternal age. As in earlier studies, the investigation found an association between congenital CMV infection and low birth weight, preterm birth, and cesarean delivery (Kharrazi M, et al. J Pediatr. 2010;157[2]:191-197).

Commentary
It may be feasible to screen newborns for congenital CMV. It isn't yet clear that we should, however. Although about 1% of children may be infected, up to 80% of infected children will never develop complications. And for the 20% who do develop CMV-related disabilities, it is not clear that we have good therapy to treat or prevent this progression. In addition, family costs-financial and emotional-may be associated with being identified and monitored. It is good to know that this technology is available. But, as with all screening tests, we need to proceed with caution. -Michael Burke, MD