Heroin and other opioids are highly reinforcing substances, which can cause substantial harm to individuals’ health over time. According to the Substance Abuse and Mental Health Services Administration (SAMHSA) [4], over two million individuals in the United States were dependent on or abused heroin and other pain relievers in 2010, with over 1 million of those reporting for treatment in the last year. Despite the widespread availability of pharmacologic and behavioral interventions for opioid addictions, significant challenges remain in tackling this public health problem. A key related public health issue is that chronic administration of opioids often takes place through intravenous injection, placing users at markedly higher risks for transmission of HIV, hepatitis C virus, and other infections, which collectively dramatically add to the health burden associated with this disorder. Additionally, dependence on prescription opiates being administered for acute or chronic pain is an emerging area of concern. Current biomarkers for opioid dependent are limited. The most commonly used screening tests in clinical practice are urine-based and have a detection limit of approximately 3–4 days for most opioids [116].
