Microcystin ELISA: Comparison of the Manual Method vs. the Automated CAAS method

Poster Presentation

Prepared by R. Read, M. Citriglia
Northeast Ohio Regional Sewer District, 4747 East 49th Street, Cuyahoga Heights, Ohio, 44125, United States

Contact Information: readr@neorsd.org; 216-641-6000


The Abraxis Cyanotoxin Automated Assay System (CAAS) is currently being used for the analysis of water samples for total microcystin/nodularin by ELISA. Use of this system provides the advantages of automation, including increased efficiency in workflow and in analyst time, and less variation in calibration/standards, providing more accurate and reliable results. Validation of the instrument for use at NEORSD included initial demonstration of capability, analysis of precision and accuracy from drinking water, and LCMRL confirmation. Additionally, results from the CAAS were compared with those from the manual method to demonstrate matching or improved performance. To increase recovery, specific parameters of the original CAAS script were changed, and results compared to both the manual method and the original script. Initial demonstration of capability results showed recoveries of 98.6%, 92.3%, and 111% of MC-LR for the manual, CAAS, and CAAS modified method, respectively. Percent recoveries were also comparable in matrix samples at 109%, 94%, and 101%. However, the manual method demonstrated higher variability for quality control and standard samples compared with the CAAS system, with the automated method providing a greater success rate for the assay.