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A comparison of reference method values for sodium, potassium and chloride with method-dependent assigned values.
Journal of Clinical Chemistry and Clinical Biochemistry. Zeitschrift Fur Klinische Chemie Und Klinische Biochemie
|December 1, 1985
Summary
Reference methods were used to measure sodium, potassium, and chloride in control sera. Ion-selective electrodes and flame photometry showed good agreement for sodium and potassium, but other methods had significant deviations.
Area of Science:
- Clinical Chemistry
- Analytical Chemistry
- Laboratory Medicine
Background:
- Accurate electrolyte measurements are crucial for patient diagnosis and treatment.
- Standardization of laboratory methods relies on comparison with established reference methods.
- Variability in analytical methods can impact clinical decision-making.
Purpose of the Study:
- To evaluate the accuracy of various analytical methods for determining sodium, potassium, and chloride concentrations in control sera.
- To compare method-dependent assigned values with reference method values.
- To assess the suitability of different techniques for routine electrolyte analysis.
Main Methods:
- Determination of electrolyte concentrations (sodium, potassium, chloride) in control sera using established reference methods.
- Comparison of results obtained from flame photometry, ion-selective electrodes, nephelometry, coulometry, and various photometric techniques against reference values.
- Statistical analysis of bias and deviation for each method.
Main Results:
- Sodium: Flame photometry and ion-selective electrodes showed <1% deviation from reference values; photometry showed -4.7% deviation.
- Potassium: Flame photometry had -1.2% bias, ion-selective electrodes had -0.4% bias; nephelometry showed -1.9% or -4.8% deviation.
- Chloride: Ion-selective electrodes (-0.3%), coulometry (-0.7%, 0.4%), and mercury rhodanide photometry (-0.5%, +0.7%) showed satisfactory agreement; mercurimetric titration (+2.5%) and a specific photometric method (+1.8%) showed larger deviations.
Conclusions:
- Ion-selective electrodes and flame photometry are reliable for sodium and potassium measurement.
- Certain photometric and titration methods for chloride exhibit significant deviations, requiring careful consideration for clinical use.
- Establishing acceptable deviation limits from reference methods is essential for ensuring the clinical validity of laboratory test results.