What advantage do ion selective analyzers using undiluted samples have?

Ion selective analyzers using undiluted samples are particularly advantageous because they are not subject to pseudohyponatremia caused by high lipids. Pseudohyponatremia occurs when the presence of high lipid levels in a sample interferes with the accurate measurement of sodium concentration, typically due to the dilution effect or interference during the analysis process. In the case of undiluted samples, the matrix effects of lipids are minimized, allowing for more accurate determinations of sodium concentration without the risk of falsely low readings that can arise in diluted samples.

Using undiluted samples helps ensure the integrity of the results, making these analyzers reliable in clinical settings where accurate sodium measurements are crucial for patient management. This specific characteristic underscores the importance of sample preparation and handling in clinical biochemistry, particularly for electrolyte analysis.