Resumen
Product water that was used to prepare hemodialysis fluids from concentrate is purified to eliminate contaminants and to ensure treatment efficacy and patient safety. Thus, the dialysis fluid should be free of solid particles. Ultrafilters are used to remove any residual bacterial contaminants from the system. In 2014 and 2016, we received two ultrafilter samples containing particulate material from two independent dialysis centers. Malfunction of the water purification system was suspected. The insoluble solid particles that were observed in ultrafilters were studied using physical techniques of Scanning Electron microscopy and Energy Dispersive X-ray spectroscopy (EDX). Spectroscopy data gathered from electron microscopy acquisition, allowed for the characterization of the elemental composition of the contaminating particles, identifying the presence of silicon and alkaline ions not belonging to the membrane or to any component of the water purification process. This material most likely represented silicate in suspension in water, reaching the ultrafilters due to a bypass in the water purification process. In conclusion, physical analysis of macroscopic ultrafilter abnormalities may help to pinpoint the source of malfunction and to provide corrective action.