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A new commercial real-time human cytomegalovirus (HCMV) PCR kit was evaluated after automated DNA extraction of 153 amniotic fluids in parallel with an in-house real-time PCR assay. The commercial kit displayed 100% sensitivity/specificity compared to the "in-house" assay and was suitable for prenatal diagnosis of HCMV congenital infection.The diagnosis of fetal human cytomegalovirus (HCMV) infection is usually made by amplification of HCMV genome in amniotic fluid (AF) sampled by amniocentesis. The overall sensitivity of HCMV DNA detection for prenatal diagnosis in AF by PCR ranges from 70 to 100% (13). However, the sensitivity of HCMV PCR in AF is close to 100% when using a PCR test and appropriate timing for amniocentesis (e.g., after 20 weeks of gestation and at least 6 weeks after maternal infection) (4). Nevertheless, false-negative HCMV PCR results have been reported in AF samples even under these optimal diagnostic conditions (5, 7, 13). These false-negative results were related to DNA amplification inhibition by inhibitory properties of AF (2). Moreover, although 100% specificity was reported for HCMV detection by PCR in AF (1, 3, 11, 13), rare cases of false-positive prenatal diagnosis have also been published (5, 7, 9). In these cases, although AF tested PCR positive, the AF culture was negative and the child was not infected at birth. False-positive results could be due to contamination occurring during PCR testing. This risk is higher with nested PCR, a technology that is very sensitive but exposed to contamination. Generalization of semiautomated real-time PCR methodology might help to overcome the risk of contamination and to achieve absolute specificity for HCMV prenatal diagnosis.In this study, we evaluated the performance of an automated DNA extraction system from AF samples to avoid cross-contamination between samples and to remove PCR inhibitors. We also compared the sensitivity, specificity, and quantification performance for amplification of HCMV in AF of a commercial real-time HCMV PCR assay including a PCR inhibitor detection system with our in-house real-time HCMV PCR assay (10).We tested 153 AF samples obtained from 153 women who presented with HCMV seroconversion in pregnancy and/or whose fetuses had ultrasound features compatible with HCMV infection. The samples were collected between

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