Accuracy of Rapid Test Strips for the Detection of the Cyanotoxin Microcystin

Abstract

Harmful Algal Blooms (HABs) pose significant risks to water quality, public health, and aquatic ecosystems, including in the Great Lakes. Traditional methods for detecting microcystin, a common cyanotoxin, often take several days to produce results, making it difficult to make timely and effective management decisions to mitigate the risks to public health posed by HABs. While some rapid tests are available, their accuracy is not well known. This study evaluated the accuracy of three brands of microcystin (MC) field test strips, Gold Standard Diagnostics (ABRAXIS® Microcystins, 0-10(20) ppb, Recreational Water with QuikLyse® Feature), Attogene (Microcystin Detection Kit (Rapid – Recreational Water)) and 5Strands (BlueGreen Algae Water Test), under varying water quality conditions and microcystin concentrations, using MC-LR (a congener of microcystin toxins) spike solution, natural bloom samples, and lab-grown Microcystis aeruginosa cultures. Gold Standard Diagnostics and Attogene both offer a range of rapid test kits tailored to different water source types including recreational water, source and finished drinking water (GSD), and both recreational and drinking water as well as a laboratory option (Attogene). Each of these brands tests for a different subset of common MC congeners, some test for only extracellular toxins (Attogene, 5Strands), and they employ different analytical methods to determine toxin concentrations; therefore, a one for one comparison is not advised. These findings reinforce the potential utility of rapid field tests as a valuable tool for timely risk assessment and monitoring of microcystin in recreational waters.