Parallel assessment of circulatory fetal DNA and corticotropin-releasing hormone mRNA in early- and late-onset preeclampsia.

strated that EtG, but not EtS, is sensitive to bacterial hydrolysis, particularly when specimens are infected by E. coli, which is the most common source of UTIs. Given that UTIs caused by E. coli are among the most frequent bacterial infections encountered in clinical practice (13 ), this represents an obvious risk factor for false-negative and falsely low EtG results. Because EtG and EtS show similar windows of detection after alcohol consumption (3 ), it may therefore be advantageous and recommended to measure EtS instead of EtG for detection or confirmation of recent drinking, or at least to combine EtG with EtS analysis, which is possible by LC-MS (3, 23 ). In any case, ensuring that specimens are refrigerated or frozen and/or that sampling tubes contain fluoride preservatives to prevent bacterial growth is recommended practice.