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Microcystin exposure and biochemical outcomes among dialysis patients
Citation:
HILBORN, E. D., R. M. Soares, A. Delgado, V. F. Magalhaes, W. W. Carmichael, J. C. Servaites, AND S. Azevedo. Microcystin exposure and biochemical outcomes among dialysis patients. Presented at Biannual International conference on Toxic Cyanobacteria, Istanbul, TURKEY, August 29 - September 04, 2010.
Impact/Purpose:
Dialysis patients appear to be at special risk for exposure to cyanobacteria toxins.
Description:
Background and aims Dialysis patients appear to be at special risk for exposure to cyanobacteria toxins; episodes of microcystin (MCYST) exposure via dialysate during 1996 and 2001 have been previously reported. During 2001, as many as 44 dialysis patients were exposed to contaminated dialysate; 12 patients were monitored for two months after detected exposure for serum MCYST concentrations and biochemical outcomes. We describe statistical analysis of serum concentrations of free MCYST to predict biochemical outcomes. Methods Drinking water used to prepare dialysate and patient sera were analyzed for MCYST using an ELISA in a research laboratory. Patient biochemical assays were performed in a hospital-based clinical laboratory. Statistical analyses included stepwise regression models predicting biochemical outcomes from serum MCYST concentrations and patient characteristics. Analyses were informed by normal ranges of biochemical values. Results Dialysis patients ranged in age from 16---80 years, 50% were male. Serum MCYST concentrations ranged from <0.16 ng/mL (LOD) to 0.96 ng/mL. Some biochemical values were outside of the normal range, but only the international normalized ratio (INR), a measure of clotting time, was associated with maximum serum MCYST concentrations. Conclusions Dialysis patients may differ from the general population, investigation of exposed, healthy individuals is needed to characterize microcystin-associated health effects. This presentation does not necessarily reflect the views and policies of the U.S. Environmental Protection Agency.