What is the role of hair analysis 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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Neonatal hair testing can also identify prenatal drug exposure. Hair begins to form at approximately 6 months' gestation; a positive result indicates use during the last trimester. Hair testing is advantageous because the specimen can be collected at any point during the first 3 months of life, after which time infant hair replaces neonatal hair. [54]

This method is useful in detecting narcotics, marijuana, cocaine, and cocaine-alcohol metabolites, but the technique is expensive, is not widely available, and is limited by the procedures required to quantify the very small amounts of drug present. Obtaining an adequate sample may be difficult, and recent exposure might not be detected because hair growth is slow.

Analysis of 1.5 cm of maternal hair reveals the maternal drug use pattern during the previous 3 months. Drug metabolites can be detected in infant hair for 2-3 months after birth.

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