Dried Blood Spot Test Reliably Detects Congenital Cytomegalovirus at Birth

Congenital cytomegalovirus (cCMV) is one of the most common infections passed from mother to child during pregnancy, affecting about 1 in 200 newborns. While many infants born with cCMV experience no lasting effects, around 20% face birth defects or long-term complications such as hearing loss and developmental delays. Early identification is essential, yet traditional tests that rely on saliva or urine samples can be cumbersome, costly, and stressful for families. Researchers have now confirmed a simpler method that can detect most cases at birth.

Scientists at the University of Minnesota Medical School in Minneapolis (Minnesota, MN, USA) evaluated the effectiveness of a PCR-based diagnostic using dried blood spots (DBS). These samples are already collected routinely in newborn screening programs, making them a practical and accessible tool. By applying molecular testing to DBS, the team aimed to streamline screening while ensuring reliability, reducing the need for additional sample collection.

The study, published in JAMA Network Open, found that the DBS test detects more than 90% of symptomatic CMV cases. This level of accuracy matches other methods while avoiding extra burdens on families and hospitals. Importantly, the test can identify infants most at risk for complications, allowing timely follow-up, interventions, and developmental monitoring to improve long-term outcomes.

These findings highlight the potential of integrating DBS-based testing into universal newborn screening programs. Minnesota already became the first U.S. state to mandate cCMV screening for all newborns in 2023, spurred by advocacy and prior research at the University of Minnesota. The new results provide strong evidence to expand adoption nationwide and internationally, with the goal of catching infections earlier and improving care strategies.

Researchers see room for refinement, aiming to boost predictive accuracy even further. With improvements, the test could potentially achieve near-perfect detection, enhancing its role in guiding interventions and policy. Broad implementation of this approach could significantly reduce the burden of cCMV by ensuring affected infants receive support from the earliest stages.

“These findings define a new path forward and a new approach to newborn care, but improvements can be made,” said Mark Schleiss, MD, professor at the University of Minnesota Medical School. “We have a test that has over 90% predictive ability to find those CMV babies that need extra help – let’s improve the test and aim for 100% accuracy.”

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University of Minnesota Medical School