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AN ENZYME-LINKED IMMUNOSORBANT ASSAY TO DETECT MICDROCYSTIN IN HUMAN SERUM
Citation:
Hilborn, E D., W. Carmichael, S. H. Azevedo, AND J. Servaites. AN ENZYME-LINKED IMMUNOSORBANT ASSAY TO DETECT MICDROCYSTIN IN HUMAN SERUM. Presented at 6th International Conference on Toxic Algae, Bergen, Norway, June 2004.
Description:
Hilborn ED 1, Carmichael WW 2 , Servaites J 2 , Yuan M2, Azevedo SMFO 3
1- USEPA/ORD/NHEERL, Research Triangle Park, NC
2- Wright State University, Dayton, OH
3- Federal University of Rio de Janeiro, Brazil
During 1996, an outbreak of fatal microcystin intoxications occurred among dialysis patients in Brazil. Using serum from affected patients, we investigated the use of a commercially-available enzyme-linked immunosorbant assay (ELISA) to detect free microcystins in human serum. We compared these results to those derived from a reference method, liquid chromatography/mass spectrometry (LC/MS) that detects free microcystin-LR-equivalents in serum.
Serum samples were gathered during the outbreak in Brazil. Samples of serum from 10 exposed persons were split. Whole serum was analyzed for microcystin concentrations by ELISA, serum supernatant was analyzed for microcystin-LR-equivalents by LC/MS. The Spearman correlation coefficient was calculated using microcystin concentrations of the two analytic methods.
Concentrations of microcystin-LR-equivalents detected by the LC/MS method ranged from 7.6?31.4 ng/ml (mean=20, median=21.2 ng/ml). Serum concentrations of total microcystins detected by the ELISA method ranged from 6.8?30.6 ng/ml (mean=19.1, median=19.9 ng/ml). There was good correlation of microcystin concentration between the two tests (Spearman r=0.99, p<0.0001).
Because the LC/MS method detects microcystin-LR-equivalents, and the ELISA method detects total microcystins in the serum, we expected ELISA-derived microcystin values to be higher. This was not seen, and it is unknown if it is due to serum or assay characteristics. The ELISA can only be considered a semi-quantitative screening method for use in human serum until method comparisons using serum from individuals with well-defined exposures can be performed.
The views expressed in this abstract are those of the individual authors and do not necessarily reflect the views and policies of the U.S. Environmental Protection Agency.