BACKGROUND: There is currently a profusion of near-patient testing devices that have been specifically targeted at drug dependency units and clinics. Some of these devices have been shown to produce accurate results. However, some devices suffer from inappropriate labeling, which together with the subjective interpretation of poorly defined reaction end-point markers, leads to misinterpretation of the results generated. METHODS: A literature search was conducted regarding the use and evaluation of near-patient testing devices for drugs-of-abuse screening. The results of this research, together our own practical evaluations of such devices, have been collated into this review. RESULTS: It is proposed that although near-patient testing devices may be useful in remote areas or where rapid action needs to be taken, it should be remembered that they provide only initial screening data and may yield false-positive or -negative results. Such devices need to be used with caution because a rapid but unconfirmed result may lead to misdiagnosis and inappropriate treatment for those who have a drug problem. It should be noted that a single result, which may be inaccurate, could lead to the cessation of treatment and a failure to provide care for those in greatest need. In addition, false-positive results may also have medico-legal implications, especially with the initiation of the drug testing and treatment orders. CONCLUSIONS: Near-patient testing devices for drugs of abuse could be an expensive and potentially inaccurate means to monitor patient treatment and drug abuse status.