Feedback on the implementation of a method by capillary electrophoresis for parenteral nutrition bags

Context

The hospital’s pharmacy produces 4400 parenteral nutrition bags per year equivalent to 3350 ion analyses. Currently the biochemistry laboratory performs these sodium and potassium ion measurements by potentiometry which has several interferences due to the complex matrix of the bags. The no. 2014-168R report from the French General Inspectorate for Social Affairs (IGAS) recommends the analytical control of sodium, potassium, calcium and magnesium ions. In order to improve the accuracy of our assays, the pharmacy department has acquired a capillary electrophoresis automaton (CE).

Objective

Evaluation of the required temporality from the analytical validation step to its implementation.

Material and method

We carried out a survey with the manipulators who did the preliminary tests of assays in order to evaluate the necessary time of their realisation with a capillary electrophoresis automaton (WynSep®).

Results

Initially, the required time for the control of a sample was estimated to 10 minutes: 2 minutes for the pre-analytical step, 5 seconds for the injection, 5 minutes of run and 2 minutes for the capillary rinse.

The validation of the method required in total the analysis of 51 samples, i.e. 11 hours : 8.5 hours of analysis and 2.5 hours of data processing.

In daily practice, it takes 60 minutes to analyze 6 samples. In addition, the monthly change of the capillary and the re-calibration require 2 hours (partial revalidation of the method).

Conclusion

This technique has the advantage of using few consumables and a small quantity of sample required for the assay. It also allows us to increase autonomy while increasing the number of detected electrolytes.

However, the implementation time of the method had been considered rather long with difficulties to appropriate the method. The control time (sample processing, analysis time and electrophoregrams interpretations) is relatively considerable if there are a large number of bags to be assayed. In addition, our automaton does not have a sample changer which monopolizes one person to the device.

CE is an interesting dosing technique despite some disadvantages related to the development and the validation of the method as well as the analysis time of the dosing of the solutes.