To conduct the screening, the researchers used a high-throughput molecular diagnostic procedure called real-time polymerase chain reaction (PCR) analysis and compared their results to the standard method for detecting CMV infection in newborns, known as the rapid culture method. Rapid culture, though highly accurate, involves a lengthy incubation and testing procedure, and is therefore not conducive to a widespread screening program.
With the PCR procedure, DNA from a sample is broken down into two separate strands. A special molecule, called a primer, seeks out a characteristic piece of CMV DNA and, if it is present, causes it to multiply and glow so it can be easily detected. To reduce the number of false positives, any babies who tested positive for CMV infection were retested using additional PCR and rapid culture tests. In addition, samples were tested directly without having to extract DNA, thereby saving considerable time and expense.
Of the infants enrolled in phase one, 85 infants were found to have CMV infection through both the rapid culture method and the PCR method; therefore, the sensitivity of PCR liquid samples was 100 percent. Of those newborns in phase two, saliva rapid culture identified CMV infection in 76 infants, 74 of which were identified with the saliva PCR; therefore, sensitivity of PCR dried samples was 97.4 percent. The researchers contend that the dry samples may be the best option for widescale screening, because this method has high sensitivity plus it is more efficient in terms of sample collection, storage, and transport.
Sixteen additional samples were found to test positive for the saliva PCR samples but not for t
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NIH/National Institute on Deafness and Other Communication Disorders