Alcohol and drug abuse are omnipresent in South Africa (SA). The United Nations Office of Drugs and Crime (UNODC) claims that 22 million people in Africa between the ages of 15 to 64 years used drugs in 2018 (UNODC World Drug Report 2021, booklet 2, Global Overview of Drug Demand and Drug Supply (www.unodc.org, accessed 15-11-2021)). This figure is forecast to escalate as Africa is predicted to have the most significant population growth in the world during the next decade.
Substance abuse is known to distort an individual’s social functioning, therefore, the percentage of individuals abusing alcohol and drugs, ending up in parental rights and responsibilities disputes, is becoming higher. Inappropriate substance use by parents is often also a contributing factor to these disputes. The percentage of investigations related to drug and alcohol abuse in parental responsibilities and rights disputes by the Office of the Family Advocate is on the rise.
The substances used by parents include legal substances, such as alcohol and cannabis, and illegal substances, such as methamphetamine (TIK), cocaine and heroin. Parents also misuse prescription and over-the-counter medications, all of which can impact their ability to exercise their parental responsibilities and rights responsibly. It is essential to keep in mind that some legitimate cannabidiol oils (CBD oil) may be contaminated with Tetrahydrocannabinol (THC), the psychoactive substance of cannabis.
This article focuses on detecting inappropriate drug and alcohol use in parental rights and responsibilities cases where allegations of substance misuse are investigated. The outcome of these investigations often disqualifies parents from having contact with their children or limits rights and responsibilities regarding decision making.
The trend in current-day SA to classify an individual’s substance use as inappropriate or problematic is to –
I submit that the abovementioned approach is incorrect and suggests that a rational, scientifically correct ‘diagnostic’ approach must be followed when classifying an individual as a problematic substance user. The analytical test results must form part of the diagnostic paradigm instead of a limited threshold approach for safety-sensitive environments where only the cut-off concentration is used to make a decision. Additional information like medical history, social function, and others must also be considered when making a rational decision in these cases.
The medical-legal questions raised must be viewed at an integrative level with a multi-layered approach, founded in the supreme provisions of the Constitution, relevant legislation, considerations of medical ethics and international due scientific practice.
Legislative framework
The legal fraternity is well versed in the legal aspects of these cases, however, detailed knowledge of scientific and legally defensible testing protocols is often not part of their knowledge base.
Legally defensible testing protocol
A sampling of biological matrices must be performed by an individual trained and registered at the HPCSA within the required field of expertise. Voluntary informed autonomous consent is required for all biomedical testing. The parent may designate a specific individual whom they deem suitable to receive the test reports or themselves only.
The sampling officer must request photographic identification and take a photo of the individual at the time of specimen collection. Anonymous submission of hair samples by courier is not ethically correct since the owner of the hair sample must provide consent.
The specimen must be collected and stored to preserve the sample’s integrity before shipping to the confirmation laboratory for testing. The chain-of-custody must also be documented.
The test results must be kept confidential and communicated on a need to know basis only, with the explicit permission of the parent or on a court order.
Medical-scientific framework
The testing protocol should involve detecting the substance with a marker of exposure first. An assessment of the amount of the substance consumed can then be done by employing a marker of effect as corroborating evidence. In the ideal case, the exposure and effect markers are identical – such markers are available for alcohol in hair.
The applicability of the matrices such as blood, urine or hair also needs to be appreciated.
Drugs and alcohol are present in the blood for a few hours, during which it is metabolised and become detectable in urine for a few days.
Confirmation analysis, with a forensically acceptable technique such as gas chromatography-mass spectrometry (GC-MS), will eliminate the uncertainty about the identity and concentration of the substance under investigation. Confirmation tests have limits of detection (LOD) that are significantly lower than screening tests and, therefore, more suitable to detect traces of drugs that are lower than the relatively high cut-off concentrations for risk-sensitive environments. The presence of a substance at a low concentration may also indicate risky behaviour by a parent. Confirmation analytical techniques are also not limited by the number of drugs that can be detected for screening tests.
Given the gravity of the decisions in parental rights and responsibilities disputes, I submit that screening tests do not have a purpose in these cases.
The analytical sensitivity and specificity of immunoassay screening tests are typically in the order of 60% to 80%. Analytical sensitivity of 70% will imply that 30% of replicate readings on the same person will not indicate the presence of a drug above the safety threshold concentration on the same specimen – 30% false-negative (FN) rate. It follows that an analytical specificity of 80% implies an incorrect detection of a drug in 20% of the replicate readings on the same person – 20% false positive (FP) rate.
Screening test results should be regarded as preliminary only. They cannot be offered as reliable evidence in any court due to their susceptibility to interferences and uncertainty in the drug concentration estimate. It is also important to note that although some screening tests are laboratory-based and performed with auto analysers on hair, blood and urine, they have the same limitations as the devices for on-site screening.
The analytical sensitivity and specificity of forensically acceptable confirmation techniques are in the order of 99, 5% for well-validated protocols operated by well qualified forensic scientists.
Markers of effect (liver enzyme induction) |
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Marker | Diagnostic sensitivity | Diagnostic specificity |
CDT | 46 – 90% | 70 – 100% |
GGT | 37 – 95% | 18 – 93% |
AST | 25 – 60% | 47 – 68% |
ALT | 15 – 40% | 50 – 57% |
Mean corpuscular volume (MCV) (anatomical changes) | 40 – 50% | 80 – 90% |
CDT+MCV+GGT (combined) |
88% | 95% |
Marker of exposure |
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EtGluc (hair) Chronic excessive drinking Cut-off = 30 Pico gram/mg hair |
75% | 96% |
TABLE 1: Biomarkers of effect and exposure and effect for chronic excessive alcohol use. Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Carbohydrate-deficient transferrin (CDT), Mean red blood cell volume (MCV), Ethyl glucuronate (EtGluc). |
In general, the diagnostic sensitivity of these effect markers for identifying chronic excessive alcohol use is not as good as the diagnostic specificity. The combination of the three effect markers CDT, MCV and GGT, has an 88% diagnostic sensitivity and 95% specificity.
These markers may also be elevated by medical disorders, which may cause FP test results, such as liver disease, genetic variations and vitamin deficiencies, among others.
It is also of prime importance not to base a decision on parents’ fitness to exercise their parental rights and responsibilities regarding their children on a medical test report only. Additional information must also be considered, such as a complete review of all history, including medical, psychiatric information, social functioning, and standardised instruments such as the Michigan Alcoholism Screening Test when alcohol abuse is investigated.
Performing a screening test only, without confirmation analysis, may be viewed as a prima facie transgression of medical ethics (in the context of the regulatory role of the HPCSA). It may also be considered a form of medical malpractice (in terms of possible civil or criminal litigation). Confirmation analysis is the best practice since the identity and concentration of the substance is confirmed, eliminating the analytical uncertainty. Screening test results should not be presented as reliable evidence in any court.
Dr Johannes B Laurens BSc (Ed) BSc (Hons) MSc (Chem) MSc (Appl Tox) (Surrey, UK) MPhil (Med Law & Ethics) PhD (Chem) PhD (Med Law) (UP) is a Director/Forensic Toxicologist at Expert Laboratory Services Pty Ltd in Pretoria and Chris Maree BCom (Law) LLB (UJ) is the Senior Family Advocate and Head of the Pretoria Office of the Family Advocate at the Department of Justice and Correctional Servies in Pretoria.
This article was first published in De Rebus in 2021 (Dec) DR 19.
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