The right dialysis fluid is checked by the electrical conductivity and regularly determination of electrolytes in the dialysis fluid.

However, I would invite all those involved in hemodialysis to periodically check the conductivity of the dialysis liquid through the concentration of the total sodium measured by the flame photometer because all the measurements carried out with the potentiometer , can have also very high sodium error percentages

In haemodialysis systems, the conductivity of the dialysis fluid (dialysate), that is being produced, is continuously monitored by a conducting cell, to verify the accuracy of proportioning of the water and concentrates forming the dialysate. The result is usually displayed as a percentage deviation from the standard. If the conductivity is not remaining within limits, an alarm is given. The effluent pump motor will be switched off automatically which effectively prevents further circulation of dialysate through the dialyzer, and the dialysate production will be by-passed to the drain. The composition of the dialysate is checked by comparing the electrical conductivity of the dialysate with a standard sample of the dialysate. Proper temperature compensation is essential as the conductivity of the dialysate changes by about (2%) for every (1 °C) change in temperature. Moreover, dialysis must never commence unless it is known that the conductivity circuit calibration and concentrate in use are both correct for the intended process. Therefore, it is recommended that once per month a sample of the dialysate from the machine's dialysate outlet connector is analyzed in a laboratory to check conductivity monitor calibration.

Regular checks on the electrolyte composition of the dialysate in addition to the electrical conductivity are routine in all dialysis centers in Germany, too. Previously, a hardness test was made in the dialysis fluid away from the dialysis center to avoid a hard water syndrome by too high calcium. Today, control of the ready-to-use dialysis fluid in the transportable Genius system is carried out by the conductivity and temperature measurement.

Already a few years ago the Italian Society of Nephrology had written the guidelines on the management of dialysis water relatively also to on-line techniques. Therefore, besides the chemical characteristics of the water to be checked regularly, the bacteriological characteristics must be checked also monthly, especially with water withdrawals at the points of arrival of the circuit to the monitors and to the connections of Monitors with Dializers. The measurement of water quality is due to laboratories outside the hospital and identified by a regional agency .This is to avoid conflicts of interest

Thank you, Ennio, for this comment. To avoid misunderstandings, it should be mentioned that bacteria do not cross the dialysis membranes due to their size, even with positive transmembrane pressure.

I agree with you Josef , however sometimes bacteria fractions and toxins can cross dialyzers membranes so is my strong conviction that diaysate must be sterile , not only in case of online treatments but in all conditions . And the gold standard should be a sterile diaysis at all'.

Dear Ennio, I agree with you, too. However, bouts of fever during dialysis which were previously explained with toxins or bacterial parts from contaminated dialysate have become very rare today, probably due to the improved production of the dialysate.

Surely the new technologies for the treatment of water for dialysis and the sterility of the system have drastically reduced the episodes of fever on dialysis. The use of the jugular vein for the insertion of central venous catheters, the use of tunneled catheters and the nursing techniques of aseptic line connection contributed to the drastic decrease of sepsis .Each dialysis center pursues its own strategy with ad hoc protocols. The use of high-or low-concentration citrate for the final filling of central venous catheters. The use of chlorhexidine instead of Betadine for the disinfection of the skin also for the insertion of the fistula needles. All strategies that require lengthy discussions, but above all a widespread conviction of the staff all: doctors and nurses.