Indications for Testing
Newborn drug testing is recommended for infants born to mothers with high-risk behaviors (eg, history of drug use/abuse, prostitution, nicotine use), minimal or no prenatal care, or unexplained obstetric events (eg, placental abruption, premature labor).
Additionally, infants with unexplained neurologic complications, unexpected intrauterine growth retardation, or drug withdrawal symptoms (eg, NAS) should be tested for drug exposure.
Available Specimen Types
ARUP offers testing of two specimen types for newborn drug testing: umbilical cord tissue and meconium. Urine as a specimen type for neonatal drug testing has limited success; the first void is often missed because it may occur during or immediately after delivery. Urine tests generally detect only recent maternal drug use in the days prior to delivery.
Newborn Drug Testing Specimen Types
| Meconium |
Umbilical Cord Tissue |
|---|
|
First stool of the newborn
Used for drug testing for ~25 yrs
Begins to form at ~12-16 wks gestation
Accumulates over remainder of pregnancy (nonlinear process)
Usually passes within 48 hrs of birth
Collection requires coordinated efforts and may not be available
Detection depends on many factors (eg, quality and completeness of collection, drug use patterns)
|
Drugs appear to deposit consistently across length of cord
Forms ~5th wk of gestation
Grows with fetus throughout pregnancy (nonlinear process)
Easy to collect at time of birth
Concentrations of drug analytes are lower in cord than in meconium, but can be detected with appropriate methods
Detection depends on many factors (eg, quality and completeness of collection, drug use patterns)
|
|
NOTE: Umbilical cord tissue and meconium drug tests are performed to support clinical and social management decisions and do not usually require chain of custody. ARUP offers a specimen tracking form for documentation of the collection, handling, and shipping of specimens. Contact ARUP Client Services for more information.
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There are several factors to consider when selecting umbilical cord tissue vs meconium for drug testing.
Umbilical Cord Tissue vs Meconium Testing
| Factors to Consider |
Umbilical Cord Tissue |
Meconium |
|---|
|
Preferred process for collection is at birth, for all infants; test immediately for high-risk births, store for low-risk births
|
X
|
|
|
Collection based on need (eg, history of drug exposure, maternal urine screen results, NAS symptoms/diagnosis)
|
X
|
X
|
|
Tracking of specimen collection and handling process required
|
X
|
X
|
|
Fastest available time to result when positive results are expected
|
X
|
|
|
Traditional testing approach (screen with reflex to confirmation testing) preferred
|
|
X
|
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Most sensitive and definitive testing for cannabis use
|
|
X
|
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Most sensitive and definitive testing for heroin use
|
X
|
|
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Preferred for the detection of the following drug(s): gabapentin, fentanyl, meperidine, propoxyphene, tramadol, tapentadol, phentermine, and/or zolpidem
|
X
|
|
|
Meconium specimen is limited or unavailable
|
X
|
|
|
Cord tissue specimen is limited or unavailable
|
|
X
|
ARUP Umbilical Cord Tissue Testing
Routine analysis by the ARUP drug detection panel includes qualitative detection by mass spectrometric methods for all compounds (eg, opioids, stimulants, sedative-hypnotics). Presence of metabolites improves confidence in results and lengthens detection window. Umbilical cord testing is thought to reflect maternal drug use during approximately the last trimester of a full-term birth. Tests to detect marijuana metabolite and ethyl glucuronide (alcohol metabolite) are available separately from the panel.
Additional Resources
Umbilical cord tissue collection instructions
Umbilical cord tissue collection video
Test Fact Sheets: ARUP Drug Detection Panel, Umbilical Cord Tissue (Qualitative) and Ethyl Glucuronide, Umbilical Cord Tissue, Qualitative
ARUP Meconium Testing
Routine analysis by the ARUP panel includes a qualitative screen for nine drug classes; specimens testing positive for one or more drugs are reflexed to confirmatory testing by highly sensitive and specific mass spectrometric methods. Directed (confirmation only) tests are available when only one drug class is of clinical interest or when quantity of meconium available for testing is very small (eg, <1 g).
The panel is the preferred meconium test to detect and document maternal drug use during pregnancy (approximately the last trimester of a full-term birth). Targeted single drug class testing is appropriate if only a particular drug class or classes are of clinical interest, or when quantity of meconium available for testing is very small (eg, <1 g).
Evaluation and Interpretation of Results
Drugs administered to the mother during labor and delivery may be detected in meconium or umbilical cord tissue. Drugs administered to the newborn after birth may be detected in meconium if the meconium is collected after drug administration.
Negative results do not exclude the possibility that the mother used drugs during pregnancy; only the drugs targeted by the testing can be detected. Maternal history and urine testing may also identify a possible infant drug exposure and should be used in combination with other laboratory results, as well as the infant’s clinical presentation, to diagnose a drug exposure.
Specimen variations can contribute to false-negative results. When definitive analytical methods (eg, liquid chromatography-tandem mass spectrometry [LC-MS/MS], gas chromatography-mass spectrometry [GC-MS]) are used, false-positive results are extremely unlikely.
Refer to the Pain and Addiction Management topic for test result interpretation organized by drug class.
Additional Resources
Opioid Metabolic Pathway
Benzodiazepine Metabolic Pathway
