The concentration of sodium (Na) in blood serum/plasma is determined by ion-specific electrode (ISE) technology that measures the physiologically important activity of sodium ions present in the aqueous (water) phase of plasma.  Two methods are available: direct ISE and indirect ISE. Direct ISE, which is employed in...

Disturbance of sodium balance is a common occurrence among hospitalized patients that can, if not identified and treated, cause significant morbidity; severe disturbance is potentially lethal. So estimation of plasma sodium concentration is one of the most frequently requested blood tests.  Historically, plasma sodium ...

Discussion of electrolyte disorders associated with diabetes is most usually confined to the abnormality of plasma/serum sodium and potassium concentrations that occur in the two acute, life-threatening, conditions of decompensated diabetes: diabetic ketoacidosis (DKA) and hyperosmolar non-ketotic coma (HNKC).   As a...

In health serum potassium concentration is maintained within the approximate reference range of 3.5-5.2 mmol/L (or 3.5-5.2 mEq/L). Hypokalemia (reduced serum potassium) is therefore defined as serum potassium <3.5 mmol/L (or <3.5 mEq/L). Severe hypokalemia (<3.0 mmol/L) is associated with muscular weakness progressing to ...

Plasma bicarbonate concentration (HCO₃^-), an essential parameter for the assessment of patient acid-base status, is routinely generated during blood gas analysis by calculation from measured pH and pCO₂. It is also directly measured by chemical analyzers in clinical laboratories that offer bicarbonate as one component ...

Increased plasma sodium concentration (hypernatremia) acquired after admission to intensive care increases the risk that critically ill patients will not survive their illness. That is the headline finding of a recently published study of ~200,000 critically patients cared for in 344 intensive care units across the US ...

The notion that acid-base and potassium homeostasis are linked is well known. Students of laboratory medicine will learn that in general acidemia (reduced blood pH) is associated with increased plasma potassium concentration (hyperkalemia), whilst alkalemia (increased blood pH) is associated with reduced plasma...

Reduced plasma calcium (hypocalcemia) is a common feature of critical illness. A recent clinical study sought to document the course of hypocalcemia during the early days of critical illness, its significance for mortality, and the efficacy of calcium supplementation. The study population comprised 1038 patients...

Emergency Department (ED) overcrowding is becoming an increasingly international issue.  Although the problem is not only resolved by ED change management (but rather requires a system-wide solution recognizing the complex interdependencies of consumer expectations, human resources, information systems immaturity and...

When monitoring the plasma/serum sodium concentration of sick newborn babies in neonatal intensive care units, it may be preferable to use direct ion-specific electrode (ISE) methodology incorporated in point-of-care analyzers (including blood gas analyzers), rather than the indirect ISE methodology commonly employed...