Garcia-Bournissen F, Rokach B, Karaskov T, et al. Methamphetamine detection in maternal and neonatal hair: implications for fetal safety (Arch Dis Child Fetal Neonatal Ed 2007;92:351–5). This paper states that positive results were confirmed by gas chromatography/mass spectrometry. The authors have clarified that some, but not all, samples that were positive by ELISA were confirmed with GC/MS; they further confirm that this fact had no impact on the results of comparing maternal to neonatal hair levels in the paper, so that the paper's conclusions remain the same.