Side-by-Side Comparison of Methods for Environmental Monitoring for Hazardous Drug Contamination

Background: Exposure to hazardous drugs is known to have deleterious effects on health care workers. To assess risk, environmental monitoring is conducted to ascertain drug contamination on surfaces, as dermal contact is the main route of exposure. Conventional monitoring employs wipe sampling whereby the wipe must be sent to a laboratory for analysis. This means that quantitative results are not available for some time, during which the risk remains unknown. A new device, the HD Check system, developed by BD, which uses lateral-flow immunoassay technology, allows for near real-time qualitative assessment of contamination (positive or negative); however, its sensitivity relative to the traditional method is unknown. Objective: To evaluate the ability of this novel device to detect drug contamination relative to the conventional method. Methods: Five sets of different known drug concentrations were compared between the conventional wipe sampling method and the HD Check systems for methotrexate (MTX) and cyclophosphamide (CP). Stainless steel surfaces were tested, and the drug concentrations ranged from 0 ng/cm(2) to twice the limit of detection (LOD) of each HD Check system. Results: For MTX, positive results were obtained in every test trial at all drug concentrations examined with the HD Check system (LOD = 0.93 ng/cm(2)). For CP, test results with the HD Check system (LOD = 4.65 ng/cm(2)) were all positive at the LOD and twice the LOD; however, at 50% and 75% of the LOD, the result was positive in only 90% (9/10) of the trials. The conventional method was able to quantify the test drug concentrations with a high level of accuracy and reproducibility. Conclusions: These results suggest the potential utility of the novel device as a screening tool for higher levels of drug contamination with MTX and CP, but additional research is needed to determine its suitability for lower concentrations, especially of CP.