What is the role of umbilical cord testing in the diagnosis of neonatal abstinence syndrome (NAS)?

Updated: Dec 20, 2017
  • Author: Ashraf H Hamdan, MD, MBBCh, MSc, MRCP, FAAP; Chief Editor: Santina A Zanelli, MD  more...
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An option for monitoring in utero drug exposure is the use of umbilical cord tissue testing. [50] A report suggested that detecting drug exposure from umbilical cord tissue has similar sensitivity and specificity to meconium samples and may have some advantages over the collection of meconium. [51]  Testing umbilical cord tissue enables analysis to occur immediately after birth, in contrast to meconium testing that is delayed up to 3 days before specimen availability. Moreover, in some cases the meconium is passed in utero, making collection impossible. Umbilical cord tissue is easily and noninvasively collected and may reflect a long window of drug detection. Negative results are usually reported the same day the specimen is received. Presumptive positive results require several days to be reported. [52]  Palmer et al showed that umbilical cord tissue toxicology testing yielded a similar detection rate compared to that from meconium testing. [53]

As a result of all these advantages, umbilical cord tissue testing is rapidly replacing meconium studies as the newborn toxicology gold standard because of its universal availability, shortened turnaround time, and improved chain of custody integrity. [52]  Although cord tissue offers many advantages from an operational perspective, the yield of testing is lower than that of meconium drug testing, and it may be difficult to draw firm conclusions about timing or duration of exposure. [49]

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