Test Catalog

Test ID: COKMX    
Cocaine and Metabolite Confirmation, Chain of Custody, Meconium

Useful For Suggests clinical disorders or settings where the test may be helpful

Detection of in utero drug exposure up to 5 months before birth


Chain of custody is required whenever the results of testing could be used in a court of law. Its purpose is to protect the rights of the individual contributing the specimen by demonstrating that it was under the control of personnel involved with testing the specimen at all times; this control implies that the opportunity for specimen tampering would be limited. Since the evidence of illicit drug use during pregnancy can be cause for separating the baby from the mother, a complete chain of custody ensures that the test results are appropriate for legal proceedings.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Cocaine is an alkaloid found in Erythroxylon coca, which grows principally in the northern South American Andes and to a lesser extent in India, Africa, and Java.(1) Cocaine is a powerfully addictive stimulant drug. Cocaine abuse has a long history and is rooted into the drug culture in the United States,(2) and is one of the most common illicit drugs of abuse.(3,4) Cocaine is rapidly metabolized primarily to benzoylecgonine, which is further metabolized to m-hydroxybenzoylecgonine (m-HOBE).(1,5) Cocaine is frequently used with other drugs, most commonly ethanol, and the simultaneous use of both drugs can be determined by the presence of the unique metabolite cocaethylene.(4)


Intrauterine drug exposure to cocaine has been associated with placental abruption, premature labor, small for gestational age status, microcephaly, and congenital anomalies (eg, cardiac and genitourinary abnormalities, necrotizing enterocolitis, and central nervous system stroke or hemorrhage).(6)


The disposition of drug in meconium, the first fecal material passed by the neonate, is not well understood. The proposed mechanism is that the fetus excretes drug into bile and amniotic fluid. Drug accumulates in meconium either by direct deposition from bile or through swallowing of amniotic fluid.(7) The first evidence of meconium in the fetal intestine appears at approximately the 10th to 12th week of gestation, and slowly moves into the colon by the 16th week of gestation.(8) Therefore, the presence of drugs in meconium has been proposed to be indicative of in utero drug exposure during the final 4 to 5 months of pregnancy, a longer historical measure than is possible by urinalysis.(7)


Chain of custody is a record of the disposition of a specimen to document each individual that collected, handled, and performed the analysis. When a specimen is submitted in this manner, analysis will be performed in such a way that it will withstand regular court scrutiny.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.


Positives are reported with a quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) result.

Cutoff concentrations for LC-MS/MS testing:

Cocaine: 20ng/g

Benzoylecgonine: 20 ng/g

Cocaethylene: 20 ng/g

m-Hydroxybenzoylecgonine: 20ng/g

Interpretation Provides information to assist in interpretation of the test results

The presence of any of the following: cocaine, benzoylecgonine, cocaethylene, or m-hydroxybenzoylecgonine, at 20 ng/g or more is indicative of in utero drug exposure up to 5 months before birth.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

No significant cautionary statements

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Isenschmid DS: Cocaine. In: Levine B, ed. Principles of Forensic Toxicology. 2nd ed. AACC Press; 2003:207-228

2. US Drug Enforcement Administration: Cocaine. DEA; 2020 Accessed 04/16/2021. Available at www.dea.gov/sites/default/files/2020-06/Cocaine-2020.pdf

3. National Institute on Drug Abuse: Cocaine DrugFacts. NIDA; 2021 Accessed 04/16/2021. Available at www.drugabuse.gov/publications/drugfacts/cocaine

4. Isenschmid DS: Cocaine-effects on human performance and behavior. Forsensic Sci Rev 2002;14:61

5. Kolbrich EA, Barnes AJ, Gorelick DA, Susan J Boyd, Edward J Cone, Marilyn A Huestis: Major and minor metabolites of cocaine in human plasma following controlled subcutaneous cocaine administration. J Anal Toxicol. 2006;30:501-510

6. Kwong TC, Ryan RM: Detection of intrauterine illicit drug exposure by newborn drug testing. National Academy of Clinical Biochemistry. Clin Chem. 1997;43:235-242

7. Ostrea EM Jr, Brady MJ, Parks PM, Asensio DC, Naluz A: Drug screening of meconium in infants of drug-dependent mothers; an alternative to urine testing. J Pediatr. 1989;115:474-477

8. Ahanya SN, Lakshmanan J, Morgan BL, Ross MG: Meconium passage in utero: mechanisms, consequences, and management. Obstet Gynecol Surv. 2005;60:45-56