Why we are recommending this best practice
- Many substances may not be detected (false negatives), including synthetic opioids and designer drugs
- Risk of false positives
- Need for confirmatory testing for any positive toxicology result
- Testing does not provide information on severity or duration of use
- Testing can only assess for current or recent use
- Even if results are negative, sporadic use is not ruled out
The evidence suggests that hospital staff are more likely to perceive black women as being at higher risk of using drugs, even though white women have similar rates of illicit drug use. Black women are therefore more likely to be tested, and more likely than white women to face punitive consequences such as having their children placed in protective care.
Even objective medical criteria for determining who should have toxicology testing may be subject to inadvertent bias. For example, “inadequate prenatal care” is a common, and often necessary, criterion for toxicology testing. If this criterion is used as a prompt for toxicology, providers and nurses must understand that a variety of factors other than substance use may influence whether a woman can remain in care, including lack of insurance, inability to take time off of work, and lack of culturally appropriate care. All these factors are more likely to impact poor women and women of color.
Strategies for implementation
- A positive urine toxicology does not equal a substance use disorder any more than a negative result rules it out.
- Ensure policies that delineate criteria for toxicology testing do not directly or indirectly target low income women and women of color.
- Behaviors (e.g. signs of acute intoxication) are more important as prompts for toxicology screening than selective indicators of risk.
- Each institution should be aware of the sensitivity and specificity of the tests they are using.
- Everyone should be familiar with the current laws and regulations for their county and state. Each institution should have a clear policy regarding what constitutes grounds for reporting to Child Protective Services (CPS) and should ensure that all staff members who work with pregnant women are educated on this policy.
- Every patient must be able to give informed consent. Informed consent requires a clear explanation of why testing is necessary, the benefits of testing, and risks of testing including the potential legal, criminal, or child welfare consequences. If the provider or nurse is unable or unwilling to thoroughly explain the typical course of events after a positive drug test at their facility, a reasonably prudent patient would not have sufficient information to make an informed decision. Additional talking points are included in the Resources section of this Best Practice.
- Every patient has a right to withhold consent and coercive language should not be used.
- Multiple biological substances can be used for toxicology testing, including urine, saliva, blood, hair, and meconium. Urine is often used to test pregnant women as the filtering action of the kidneys allows detection of smaller quantities for a longer period than blood.
- Toxicology tests generally fall into two types: screening tests and confirmatory tests.
- It is essential to confirm unexpected results from toxicology screening tests. If the result of the screening test matches an expected result, it is usually not necessary to obtain confirmatory testing. Examples of unexpected results might include:
- A patient tests positive for a substance that she denies taking
- A patient tests negative for a substance that is prescribed, and she indicates she is taking regularly
- Toxicology testing does not provide information on how recently someone used a substance or the quantity they used. Toxicology screening tests are qualitative and only indicate the presence/absence of a substance. Confirmatory testing often does report a quantitative level, but this should not be used to infer how much a woman is using a substance. Many factors are involved, and any value over the cutoff level should be a qualitative positive unless evaluated by a medical review officer.
- Urine drug toxicology on admission to the hospital need to be monitored for timing of the sample related to administration of intrapartum pain medications. Fentanyl can lead to false positive opioid results. Ephedrine and vasopressin can lead to false positive amphetamine.
- For an excellent review of drug screening immunoassays for clinicians to become proficient in understanding and interpretation of results, please see Nelson ZJ et al. They also provide a full description of false positives and false negatives.
- Kunins HV, Bellin E, Chazotte C, Du E, Arnsten JH. The Effect of Race on Provider Decisions to Test for Illicit Drug Use in The Peripartum Setting. Journal of Womens Health. 2007;16(2):245-255. doi:10.1089/jwh.2006.0070.
- ACOG Committee Opinion No 711: Opioid Use and Opioid Use Disorder in Pregnancy. Obstet Gynecol. 2017;130: e81-94.
- Hospital staff more likely to screen minority mothers. Los Angeles Daily News. June 30, 2009. https://www.dailynews.com/2008/06/30/hospital-staff-more-likely-to-screen-minority-mothers/ Accessed June 14, 2019.
- Chasnoff IJ, Landress HJ, Barrett ME. The Prevalence of Illicit-Drug or Alcohol Use during Pregnancy and Discrepancies in Mandatory Reporting in Pinellas County, Florida. New England Journal of Medicine. 1990;322(17):1202-1206. doi:10.1056/nejm199004263221706.
- Gonzalez, S. Ye, J. Black Mothers Judged Unfit at Higher Rate than White Mothers in NJ. WNYC News. New York Public Radio. May 26, 2015. https://www.wnyc.org/story/black-parents-nj-lose-custody-their-kids-more-anyone-else/ Accessed June 14, 2019.
- National Advocates for Pregnant Women. Memo: Standards for Drug Testing Pregnant Women, New Mothers & Newborns. March 2014.
- Appropriate Use of Drug Testing in Clinical Addiction Medicine. Journal of Addiction Medicine. 2017;11:1-56. doi:10.1097/adm.0000000000000322.
- Barthwell AG, Allgaier J, Egli K. Definitive urine drug testing in office-based opioid treatment: a literature review. Critical Reviews in Toxicology. 2018;48(10):815-838. doi:10.1080/10408444.2018.1553935.
- Nelson ZJ, Stellpflug SJ, Engebretsen KM. What can a urine drug screening immunoassay really tell us? J Pharm Pract. 2016;29(5):516-26.