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Meconium Drug ScreenAka: Toxicology Screening of Meconium

Indication
1. Suspected Substance Abuse in Pregnancy
Mechanism
1. Meconium accumulates drug exposure throughout pregnancy
2. In utero exposure of drugs implied by positive test
  1. Exposure may have been months prior to delivery
General
1. Lab testing methadology is critical to efficacy
2. Screening Tests are non-specific
3. Confirmatory testing is highly specific
  1. Gas chromatography mass spectrometry (GC/MS)
  2. Liquid Chromatography mass spectrometry (LC/MS)
Efficacy
1. False positives if infant urinates into sample
  1. Reflects antepartum and perinatal esposure
2. False negatives
  1. Meconium sample at room temperature
    1. Decreases Cocaine and cannabinoid by 25% per day
  2. Preterm Infant
Drug Screening (sensitive, but not specific)
1. Opiates
  1. May be positive due to codeine, heroin, morphine
  2. Less sensitive for Oxycodone and hydrocodone
  3. Heroin clears very quickly
    1. However 6-acetylmorphine metabolite clears slowly
2. Cocaine
  1. Multiple metabolites may be measured
  2. False positive is very rare
    1. Theororetically Lidocaine can cause positive
    2. In reality, Lidocaine ammount required too high
3. Amphetamines
  1. Methamphetamine metabolized to Amphetamine
  2. MDMA (Ecstacy) metabolized to MDA
  3. MDA and Amphetamine may appear similar on testing
4. Cannabinoids (Marijuana)
References
1. Lesler (2001) Pediatrics 107:309
2. Ostrea (2001) J Pediatr 138:344

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This page was written by Scott Moses, MD. This page was last revised before 5/10/08, prior to consistent tracking of revision date. This page was last published on 6/1/2008. Please send comments and questions to the editor. Contact information may be found on the page About the Family Practice Notebook. These pages are best viewed with Microsoft Internet Explorer 6.0.