Abstract
Our objective was to investigate the methodologic detection of cocaine abuse during pregnancy by determining the viability of meconium analysis for cocaine and its metabolites using chromatographic procedures as an alternative to urine testing using enzyme multiplied immunoassay technique.
Our design was as follows: meconium and urine were taken from 106 very low birthweight premature babies. Meconium analysis for cocaine and its metabolites using extraction and chromatographic analysis was compared with the criterion standard immunoassay testing for urine.
The work was carried out at The University of Chicago Hospital, Department of Pediatrics and the University of Illinois at Chicago, Department of Pharmacodynamics. Our patients were very low birthweight, premature babies (mean birthweight 1109 g; mean gestational age 29.1 weeks). Gender was evenly divided between male and female.
The outcome measures were as follows: two active metabolites, norcocaine and cocaethylene, were detected in the meconium, but not in the urine, of some of the neonates. Determination of cocaine exposure in the newborn influenced assignment of babies in research studies as well as psychosocial evaluation and subsequent treatment of the neonate.
Our results were: of the 106 meconium samples analyzed, 21 (19.8%) were positive for cocaine (n = 19, 0.24–0.78 mg/kg), norcocaine (n = 7, 0.10–0.56 mg/kg), cocaethylene (n = 1, 0.12 mg/kg) or combinations thereof. Benzoylecgonine was not detected in any of the samples. Of the urine samples analyzed by immunoassay, only 8 (7.5%) were positive for cocaine metabolites.
We conclude that meconium is a better sample than urine for determining cocaine exposure in utero. The presence of two neuroactive metabolites, norcocaine and cocaethylene, is reported, norcocaine for the first time. Immunoassay screening procedures for urinalysis are inadequate because false-negative results are obtained.
