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Test ID THCMX 11-nor-Delta-9-Tetrahydrocannabinol-9-Carboxylic Acid (Carboxy-THC) Confirmation, Chain of Custody, Meconium

Useful For

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.

Additional Tests

Test ID Reporting Name Available Separately Always Performed
COCH Chain of Custody Processing No Yes

Reporting Name

Carboxy-THC Confirmation, CoC, M

Specimen Type

Meconium


Specimen Required


Container/Tube: Chain-of-Custody Meconium Kit (T653) includes the specimen containers, seals, and documentation required.

Specimen Volume: 1 g (approximately 1 teaspoon)

Collection Instructions: Collect entire random meconium specimen.

Additional Information:

1. Specimen that arrives with a broken seal does not meet the chain of custody requirements.

2. The laboratory recommends sending chain-of-custody specimens by overnight shipment.


Specimen Minimum Volume

0.3 g (approximately 1/4 teaspoon)

Specimen Stability Information

Specimen Type Temperature Time
Meconium Frozen (preferred) 28 days
  Refrigerated  21 days
  Ambient  14 days

Clinical Information

Marijuana and other psychoactive products obtained from the plant Cannabis sativa are the most widely used illicit drugs in the world.(1) Marijuana has unique behavioral effects that include feelings of euphoria and relaxation, altered time perception, impaired learning and memory, lack of concentration, and mood changes (eg, panic reactions and paranoia).

 

Cannabis sativa produces numerous compounds collectively known as cannabinoids including delta-9-tetrahydrocannabinol (THC), which is the most prevalent and produces most of the characteristic pharmacological effects of smoked marijuana.(2) THC undergoes rapid hydroxylation by the cytochrome (CYP) enzyme system to form the active metabolite 11-hydroxy-THC. Subsequent oxidation of 11-hydroxy-THC produces the inactive metabolite 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH; carboxy-THC). THC-COOH and its glucuronide conjugate have been identified as the major end-products of metabolism. THC is highly lipid soluble, resulting in its concentration and prolonged retention in fat tissue.(3)

 

Cannabinoids cross the placenta, but a dose-response relationship or correlation has not been established between the amount of marijuana use in pregnancy and the levels of cannabinoids found in meconium, the first fecal matter passed by the neonate.(4,5) The disposition of drug in meconium 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 amniotic fluid.(5) 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.(6) 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.(5)

 

Chain of custody is a record of the disposition of a specimen to document who collected it, who handled it, and who 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

Negative

Positives are reported with a quantitative LC-MS/MS result.

Cutoff concentrations

Tetrahydrocannabinol carboxylic acid (marijuana metabolite) by LC-MS/MS: 10 ng/g

Interpretation

The presence of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid ≥10 ng/g is indicative of in utero drug exposure up to 5 months before birth.

Clinical Reference

1. Huestis MA: Marijuana. In Principles of Forensic Toxicology. Second edition. Edited by B Levine. Washington DC, AACC Press, 2003 pp 229-264

2. O'Brein CP: Drug addiction and drug abuse. In Goodman and Gilman's The Pharmacological Basis of Therapeutics. 11th edition. Edited by LL Burton, JS Lazo, KL Parker. McGraw-Hill Companies Inc, 2006. Available at URL: www.accessmedicine.com/content.aspx?aID=941547

3. Baselt RC: Tetrahydrocannabinol. In Disposition of Toxic Drugs and Chemical in Man. Edited by RC Baselt. Foster City, CA, Biomedical Publications, 2008: pp1513-1518

4. Ostrea EM Jr, Knapop DK, Tannenbaum L, et al: Estimates of illicit drug use during pregnancy by maternal interview, hair analysis, and meconium analysis. J Pediatr 2001;138:344-348

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

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

Day(s) and Time(s) Performed

Monday through Friday, Sunday; Varies

Analytic Time

2 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

80349

G0480 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
THCMX Carboxy-THC Confirmation, CoC, M 69007-3

 

Result ID Test Result Name Result LOINC Value
36305 THC 69007-3
36306 Interpretation 69050-3
36307 Chain of Custody No LOINC Needed

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)