Diestro 103APV4R, Руководство оператора и по обслуживанию

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DIESTRO 103APV4R ELECTROLYTE ANALYZER
127 JS Medicina Electrónica
ANNEX III - PRINCIPLE OF OPERATION
Measurement technology
There are two different technologies for electrolyte measurement, commonly known as Direct
ISE and Indirect ISE (ISE = Ion-selective electrode).
ISE Direct
The measurement is performed directly on the sample of whole blood, plasma or serum.
The use of whole blood does not involve prior preparation of the sample.
The Direct ISE measures the activity of the electrolyte in plasma (mmol/Kg H2O), or "plasma
concentration (mmol/L)". The electrochemical activity of ions in water is converted into the
corresponding concentration by means of an Ion-specific factor. This is only applicable for a
given concentration range. The use of this factor ensures that the Direct ISE reflects the current
situation, activity of clinical relevance, regardless of the values of proteins and / or lipids.
However, the result is traditionally called "concentration". This conversion is based on
recommendations from the IFCC Expert Panel on pH and Bood Gases, in order to avoid the
confusion of having two types of electrolyte results.
This technology is typically used in Blood Gas Analyzers and Point of Care Analyzers.
The reported result is independent of the solids content of the sample.
The results obtained through the Direct ISE correlate well when working with samples with
normal lipid and protein content. This obviously requires the elimination of pre-analytical errors.
The Analyzer uses the Direct Selective Ion method for the determination of electrolytes.
It is based on the properties of its transducers or sensors (electrodes) to be selective to a
specific Ion in solution.
This is achieved thanks to the fact that the membranes of the selective Ion Electrodes develop a
potential (with respect to a Reference electrode) proportional to the activity of the Ion in solution
for which they are selective.
This potential obeys the Nernst equation.