Rapid Cyanide Detection Using the Cyantesmo® Kit

Abstract

Background: Sources of cyanide exposure are many, including combustion of plastic and vinyl, such as in a house fire, laboratory or industrial exposures including exposure in the electroplating industry both of printed circuit boards and in jewelry work. Rapid and definitive diagnosis of cyanide poisoning is unavailable in the emergency department setting. It is desirable to make a definitive diagnosis in order to prevent potential complications of empiric treatment of presumptive cyanide poisoning from the cyanide antidote kit currently approved by the US Food and Drug Administration (FDA). We investigated a technique to detect cyanide currently utilized by water treatment facilities to determine if it can be applied to rapidly detect concentrations of cyanide in the clinically important range. Methods: Varying standardized dilutions of KCN ranging from 0.25 µg/mL to 30 µg/mL were acidified with a drop of sulphuric acid in a closed system under a ventilation hood. Cyantesmo® test strips were placed into the test tubes above the fluid level where liberated HCN gas interacted with the test strip to effect a color change. Color changes were compared to negative controls and to each other. Results: The test strips demonstrated an incrementally increasing deep blue color change over a progressively longer portion of the test strip in less than 5 minutes for each concentration of KCN including 1, 3, 10, and 30 µg/mL. The concentrations of 0.25, 0.5, and 0.75 required more than 2 hours to begin demonstration of any color change. Conclusion: The Cyantesmo® test strips accurately and rapidly detected, in a semi‐quantifiable manner, concentrations of CN greater than 1 µg/mL contained in each test sample. Future work to validate this test in blood and in clinical specimens is planned.