Biological Testing and Interpretation of Laboratory Results Associated with Detecting Newborns with Substance Exposure

BACKGROUND

Substance use during pregnancy is common, as is biological testing that is intended to help identify prenatal exposures. However, there is no standardized requirement for biological testing with either maternal or newborn specimens, nor is there standardization related to when testing occurs, how frequently testing occurs, what specimen(s) to test, what substances to test for, or how to perform testing.

CONTENT

We review common specimen types tested to detect maternal and newborn substance exposure with a focus on urine, meconium, and umbilical cord tissue. We also review common analytical methods used to perform testing, including immunoassay, and mass spectrometry platforms. Considerations regarding the utilization of testing relative to the purpose of testing, the drug analyte(s) of interest, the specific testing employed, and the interpretation of results are emphasized to help guide decisions about clinical utilization of testing. We also highlight specific examples of unexpected results that can be used to guide interpretation and appropriate next steps.

SUMMARY

There are strengths and limitations associated with all approaches to detecting substance exposure in pregnant persons as well as biological testing to evaluate a newborn with possible substance exposure. Standardization is needed to better inform decisions surrounding evaluation of substance exposures in pregnant people and newborns. If biological sampling is pursued, testing options and results must be reviewed in clinical context, acknowledging that false-positive and -negative results can and do occur.

Integrated vs nonintegrated treatment for perinatal opioid use disorder: retrospective cohort study

BACKGROUND

Pregnant women with opioid use disorder and their infants often experience worse perinatal outcomes than women without opioid use disorder, including longer hospitalizations after delivery and a higher risk for preterm delivery. Integrated treatment models, which combine addiction treatment and maternity care, represent an innovative approach that is widely endorsed, however, limited studies have compared the outcomes between integrated and standard, nonintegrated programs from real-world programs.

OBJECTIVE

This study aimed to evaluate the perinatal and substance use outcomes for pregnant women with opioid use disorder receiving coordinated, colocated obstetrical care and opioid use disorder treatment (integrated treatment) and to compare it with those of women receiving obstetrical care and opioid use disorder treatment in distinct programs of care (nonintegrated treatment).

STUDY DESIGN

In this observational, retrospective cohort study, we abstracted the perinatal and opioid use disorder treatment data from the records of pregnant women with opioid use disorder (n=225) who delivered at a rural, academic medical center from 2015 to 2017. The women either received integrated (n=92) or nonintegrated (n=133) opioid use disorder treatment and obstetrical care. Using inverse probability weighted regression models to adjust for a potential covariate imbalance, we evaluated the impact of the treatment model on the risk for preterm delivery and positive meconium or umbilical cord toxicology screens. We explored whether the number of obstetrical visits mediated this relationship by using a quasi-Bayesian Monte Carlo algorithm.

RESULTS

Women receiving integrated treatment were less likely to deliver prematurely (11.8% vs 26.6%; P<.001) and their infants had shorter hospitalizations (6.5±4.8 vs 10.7±16.2 days). Using a robust inverse probability weighted model showed that receiving integrated treatment was associated with a 74.7% decrease in the predicted probability of preterm delivery (average treatment effect, -0.19; standard error, 0.14; P<.001). There were no differences in the risk for a positive meconium or umbilical cord toxicology screen, a marker for second and third trimester substance use, between women receiving integrated treatment and those receiving coordinated treatment (29.4% vs 34.6%; P=.41), however, integrated treatment was associated with significantly lower rates of positive maternal urine toxicology screens at the time of delivery (35.9% vs 74.4%; P<.001).

CONCLUSION

Among a cohort of rural pregnant women with opioid use disorder, receiving integrated obstetrical care and opioid use disorder treatment was associated with a reduced risk for preterm birth, a lower risk for positive maternal urine toxicology screen at the time of delivery, and shorter infant hospitalization. This relationship was mediated by the number of obstetrical visits attended during pregnancy, suggesting that increased engagement with obstetrical care through integration of services may contribute to improved perinatal outcomes.

Alternative matrices in forensic toxicology: a critical review

Purpose

The use of alternative matrices in toxicological analyses has been on the rise in clinical and forensic settings. Specimens alternative to blood and urine are useful in providing additional information regarding drug exposure and analytical benefits. The goal of this paper is to present a critical review on the most recent literature regarding the application of six common alternative matrices, i.e., oral fluid, hair, sweat, meconium, breast milk and vitreous humor in forensic toxicology.

Methods

The recent literature have been searched and reviewed for the characteristics, advantages and limitations of oral fluid, hair, sweat, meconium, breast milk and vitreous humor and its applications in the analysis of traditional drugs of abuse and novel psychoactive substances (NPS).

Results

This paper outlines the properties of six biological matrices that have been used in forensic analyses, as alternatives to whole blood and urine specimens. Each of this matrix has benefits in regards to sampling, extraction, detection window, typical drug levels and other aspects. However, theses matrices have also limitations such as limited incorporation of drugs (according to physical–chemical properties), impossibility to correlate the concentrations for effects, low levels of xenobiotics and ultimately the need for more sensitive analysis. For more traditional drugs of abuse (e.g., cocaine and amphetamines), there are already data available on the detection in alternative matrices. However, data on the determination of emerging drugs such as the NPS in alternative biological matrices are more limited.

Conclusions

Alternative biological fluids are important specimens in forensic toxicology. These matrices have been increasingly reported over the years, and this dynamic will probably continue in the future, especially considering their inherent advantages and the possibility to be used when blood or urine are unavailable. However, one should be aware that these matrices have limitations and particular properties, and the findings obtained from the analysis of these specimens may vary according to the type of matrix. As a potential perspective in forensic toxicology, the topic of alternative matrices will be continuously explored, especially emphasizing NPS.

Umbilical Cord Drug Screening in Multiple Births: Experience from a Reference Laboratory and Academic Medical Center

The objective of this study was to review the results of umbilical cord drug screening in twins and triplets (multiples) to compare drug(s) and/or drug metabolite(s) detected. Results that did not agree between multiples were considered mismatched and were investigated. A retrospective analysis was conducted using de-identified data from a national reference laboratory, and results were compared with data from an academic medical center, where detailed medical chart review was performed. Umbilical cord was analyzed for stimulants, sedatives, opioids, and other drugs and metabolites. For the reference laboratory dataset, 23.3% (n=844) of 3,616 umbilical cords from twins (n=3,550) or triplets (n=66) were positive for one or more drugs and/or metabolites. Of these, mismatched results were identified for thirty-seven sets of twins (2.1%) and no sets of triplets. The most frequent mismatches were found in opioids (n=24), with morphine (n=5) being the most mismatched of any single analyte in the panel. Mismatches for the marijuana metabolite 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (9-COOH-THC) in the reference laboratory dataset occurred in six of 737 sets of twins (0.8%) and no triplets. For the academic medical center dataset, 21.9% (n=57) of 260 umbilical cords tested positive for one or more drugs and/or metabolite(s). Of these, 4 mismatches (3.2%) were identified, including 9-COOH-THC (n=2), phentermine (n=1), and oxycodone (n=1), all involving twins. All involved cases where the discrepant analyte was likely present in the negative twin but either slightly below reporting cutoff threshold, or failed analytical quality criteria. Mismatched results of umbilical cord drug screening occur in less than 4% of twins and most often occur when the analyte is slightly above the reporting cutoff in just one infant.

Neonatal Exposure to Tramadol through Mother's Breast Milk

Tramadol is an opioid used in the treatment of moderate to moderately severe pain. Tramadol's use during pregnancy is generally avoided and may cause some reversible withdrawal effects in neonates and its use during lactation is not licensed by the manufacturer. A small clinical trial reported infants were exposed to < 3% of a mother's tramadol dose though breast milk with no evidence of harmful effects. Presented is a case study of breast milk, neonatal urine, and neonatal oral fluid for the analysis of tramadol and its metabolites, along with the validation of a method for the analysis of tramadol, O-desmethyltramadol, and N-desmethyltramadol in breast milk. Tramadol and its metabolites were extracted by solid-phase extraction (SPE) after saponification of breast milk to remove lipids. Samples were analyzed by ultra-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). To the author's knowledge, this is the first report of tramadol and its metabolites in neonatal oral fluid. The breast milk concentrations were 63, 22, and 76 ng/mL tramadol, O-desmethyltramadol and N-desmethyltramadol, respectively on day of life 12. On day of life 20, the breast milk concentrations were 1,254, 388, and 937 ng/mL tramadol, O-desmethyltramadol and N-desmethyltramadol, respectively. Oral fluid concentrations were 1,011, 1,499, and 406 ng/mL tramadol, O-desmethyltramadol and N-desmethyltramadol, respectively on day of life 20. Oral fluid concentrations were similar to breast milk for tramadol, almost four times higher for O-desmethyltramadol, and less than half for N-desmethyltramadol. The absolute infant dose was calculated to be 10 μg/kg/day and 294 μg/kg/day tramadol on day of life 12 and 20, respectively.

Testing Unconventional Matrices to Monitor for Prenatal Exposure to Heroin, Cocaine, Amphetamines, Synthetic Cathinones, and Synthetic Opioids

BACKGROUND

The prevalence of drug use during pregnancy continues to increase despite the associated serious adverse obstetrical outcomes, including increased risk of miscarriage, fetal growth restriction, brain development impairment, neonatal abstinence syndrome, preterm delivery, and stillbirths. Monitoring drug use during pregnancy is crucial to limit prenatal exposure and provide suitable obstetrical health care. The authors reviewed published literature reporting the concentrations of common drugs of abuse and new psychoactive substances (NPS), such as synthetic cathinones and synthetic opioids, NPS, and their metabolites using unconventional matrices to identify drug use during pregnancy and improve data interpretation.

METHODS

A literature search was performed from 2010 to July 2019 using PubMed, Scopus, Web of Science scientific databases, and reports from international institutions to review recently published articles on heroin, cocaine, amphetamine, methamphetamine, synthetic cathinone, and synthetic opioid monitoring during pregnancy.

RESULTS

Meconium has been tested for decades to document prenatal exposure to drugs, but data regarding drug concentrations in amniotic fluid, the placenta, the umbilical cord, and neonatal hair are still lacking. Data on prenatal exposure to NPS are limited.

CONCLUSIONS

Maternal hair testing is the most sensitive alternative matrix for identifying drug use during pregnancy, while drug concentrations in the meconium, placenta, and umbilical cord offer the identification of prenatal drug exposure at birth. Adverse developmental outcomes for the infant make it critical to promptly identify maternal drug use to limit fetal exposure or, if determined at birth, to provide resources to the exposed child and family. Alternative matrices offer choices for monitoring and challenge laboratories to deliver highly sensitive and specific analytical methods for detection.

A Case Study Evaluating the Efficacy of an Ad Hoc Hospital Collection Device for Fentanyl in Infant Oral Fluid

Neonatal drug exposure is currently assessed using meconium, urine, blood, hair, or umbilical cord tissue/blood. Due to the invasiveness, challenges, and limitations of collection, and/or analytical difficulties of these matrices, oral fluid may be a more desirable matrix in diagnosing opioid exposure and risk for opioid withdrawal in neonatal abstinence syndrome. Traditional oral fluid collection devices are not viable options as they are too large for neonates' mouths and may contain chemicals on the collection pad. Unstimulated and stimulated infant oral fluid samples have been used for therapeutic drug monitoring as an alternative matrix to blood. The objective of this study was to assess the viability of a simple oral fluid collection system using a sterile foam-tipped swab rinsed in phosphate-buffered saline. Two infants were administered fentanyl for post-operative pain relief while hospitalized in the Neonatal Intensive Care Units at the Children's Hospital of Richmond of Virginia Commonwealth University. Oral fluid samples were collected at 16 h, 2 days, and/or 7 days following the start of intravenous infusion of fentanyl. Samples were analyzed by ultra-high-pressure liquid chromatography-tandem mass spectrometry for fentanyl and norfentanyl after solid-phase extraction. In one of the three samples tested, fentanyl and norfentanyl were detected at concentrations of 28 and 78 ng/mL, respectively. Based on the infusion rate, the theoretical oral fluid fentanyl concentration at steady state was calculated to be 33 ng/mL.

Umbilical Cord Tissue and Meconium May Not Be Equivalent for Confirming in Utero Substance Exposure

In a retrospective study of 501 neonates with potential in utero substance exposure, the drug detection performance of a commercially available umbilical cord tissue toxicology test was evaluated against a commercially available gold standard meconium toxicology test. Drugs detected in paired meconium and umbilical cord tissue samples were often discordant.

Simultaneous accelerated solvent extraction and hydrolysis of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in meconium samples for gas chromatography-mass spectrometry analysis

Cannabis misuse during pregnancy is associated with severe impacts on the mother and baby health, such as newborn low birth weight, growth restriction, pre-term birth, neurobehavioral and developmental deficits. In most of the cases, drug abuse is omitted or denied by the mothers. Thus, toxicological analyzes using maternal-fetal matrices takes place as a suitable tool to assess drug use. Herein, meconium was the chosen matrix to evaluate cannabis exposure through identification and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic (THCCOOH). Accelerated solvent extraction (ASE) was applied for sample preparation technique to simultaneously extract and hydrolyze conjugated THCCOOH from meconium, followed by a solid-phase extraction (SPE) procedure. The method was developed and validated for gas chromatography-mass spectrometry (GC-MS), reaching hydrolysis efficiency of 98%. Limits of detection (LOD) and quantification (LOQ) were, respectively, 5 and 10 ng/g. The range of linearity was LOQ to 500 ng/g. Inter and intra-batch coefficients of variation were <8.4% for all concentration levels. Accuracy was in 101.7-108.9% range. Recovery was on average 60.3%. Carryover effect was not observed. The procedure was applied in six meconium samples from babies whose mothers were drug users and showed satisfactory performance to confirm fetal cannabis exposure.

Comparison of umbilical cord tissue and meconium for the confirmation of in utero drug exposure

OBJECTIVES

Drug screening in neonates is traditionally performed using meconium, but cord tissue has been proposed as an alternative specimen. This study compares the detection of drugs in a large number of paired meconium and umbilical cord tissue samples from subjects at risk of in utero drug exposure.

DESIGN AND METHODS

Physician-ordered toxicology results and clinical information were collected in a retrospective review of subject medical records. All toxicology testing was performed by a national reference laboratory using a combination of immunoassays and chromatography-mass spectrometry. The comparison was limited to drugs present in both cord and meconium panels.

RESULTS

Overall agreement between cord and meconium ranged from 76% (cannabinoids) to 100% (barbiturates), but Cohen's kappa was <65% for 5 of the 6 drug classes we studied. Considering meconium as the gold standard, cord was less sensitive for the detection of 5 of the 6 drug classes, and for the detection of all 5 individual opioids. For 3 of the 5 individual opioids, the concentration of drug measured in meconium did not correlate well with qualitative detection in cord.

CONCLUSIONS

This study reveals different sensitivities of drug detection in umbilical cord tissue and meconium. For the drugs studied here, meconium provides greater sensitivity, and is likely to remain the specimen of choice when sensitivity is of greatest importance. These results can help clinicians, laboratorians, and epidemiologists to (1) select the most appropriate test to confirm a suspected drug exposure and (2) interpret discordant results when testing is performed in multiple matrices.