Drug Toxicology Testing

Except in life-threatening situations where informed consent is impossible, adults must give informed consent before they are tested for drugs.

In cases of child protection concerns, neonatal toxicology testing may be performed without consent of the parent(s), if the person requesting this testing has a legislative right to make decisions for that child.

Urine Drug Screening (UDS)

Immunoassay more sensitive: screens for classes of drugs and some specific drugs
Chromatography more specific: detects specific drugs
Confirmatory testing, using at least 2 methods of testing, is essential if there are legal or custody implications for results
Also ensure clear chain of custody of specimen between woman providing sample and laboratory testing e.g., supervised sample collection
Detection times depend on numerous factors including urine concentration, individual health status, drug metabolism and half-life; meant as a guide since some results may fall outside ranges

Urine Drug Screening

Drug	Chromatography – Days Detected	Immunoassay – Days Detected
Opiates Codeine Morphine Meperidine Hydromorphone Hydrocodone Oxycodone	1-2	3-5 Does not differentiate between various opiates Synthetic and semisynthetic opiates (oxycodone, meperidine, methadone) often missed False positives: quinolone antibiotics, poppy seeds Both codeine and morphine are detected with codeine use
Benzodiazepines (Chronic Use)	Days-weeks, depending on half-life	20+ Clonazepam sometimes missed
Cannabis (Chronic Use)	n/a	20+
Cocaine	1-2 (parent drug)	3-5 (benzoylecgonine - cocaine metabolite)
Amphetamine e.g., methamphetamine, MDMA (ecstasy)	1-2	2-3 (Cross reacts with decongestants and antipsychotics)

Hair and Meconium Testing

Hair and meconium testing are alternate biological markers for longitudinal exposure to alcohol and drugs. These tests are rarely used in clinical practice due to several limitations and are currently ordered for legal reasons. Both hair and meconium testing cannot pinpoint the specific time nor the exact amount and length of an individual’s drug use.

Hair Testing

o Can be done with both maternal and newborn hair

o Newborn hair starts growing in third trimester of pregnancy indicating in utero exposure to substances

o Hair analysis can detect a broad range of drugs including opiates, cocaine, cannabis, benzodiazepines, barbiturates, amphetamines and other drugs

Meconium Testing

o Represents newborn’s first stool, blackish in colour

o Starts forming in second trimester of pregnancy indicating in utero substance exposure

o Testing can detect exposure t alcohol, opiates, cocaine, cannabis, barbiturates, amphetamines and others

This site last edited: June 2008

General Prenatal Care