Standard methods for the microbiological assessment of electrolyte solution prepared on line for haemofiltration

The preparation of large volumes of intravenous solution at the bedside (on-line preparation) requires bacteriological monitoring and pyrogen control before final sterilisation. We tested the sensitivity of microbiological methods and their applicability in routine clinical conditions during haemofiltration. In vitro, the 0.22 micron membrane filter technique (MF) showed a better or equal bacterial recovery with two test organisms. Parallel tests of 0.22 and 0.45 micron MF under simulated haemofiltration conditions showed no significant difference in the number of detected bacteria. Routine MF with 0.22 micron membranes offers a simple and reliable way to monitor the bacterial content of on-line prepared electrolyte solution in clinical conditions.