In health plasma/serum potassium (K⁺) is maintained within the approximate reference range of 3.5 to 5.2 mmol/L, with serum values being slightly higher (∼ 0.4 mmol/L) than those of plasma because the process of blood clotting, essential to recovery of serum samples, is associated with release of potassium from...

Transfusion of donated (allogenic) red blood cells is of undoubted life-saving benefit to those suffering rapid and massive blood loss (hemorrhage) due to major trauma, or complications during surgery and childbirth. However, the procedure is not without risk, and accumulated evidence over the past 2 decades has...

This paper is an up-to-date account of research and current clinical practice guideline recommendations. Chris Higgins summarizes the recommendations of 2 new guidance documents on the use of natriuretic peptides in heart failure. The first document is a systematic review of published research (up to 2016) on the role ...

This article reviews the results of recent clinical studies on measuring lactate in arterial versus capillary blood. While arterial blood is the gold standard sample for lactate measurement on blood gas and other point-of-care analyzers, capillary blood is an alternative sample for lactate measurement on hand-held...

This article discusses the use of citrate anticoagulation during continuous renal replacement therapies (CRRTs) which are prescribed for patients with severe acute kidney injury (AKI). Where heparin was traditionally the anticoagulant of choice for CRRT, regional citrate anticoagulation (RCA) has now emerged as the...

This article evaluates venous blood as an alternative to arterial blood for lactate measurement, highlighting the general considerations related to each of the three types of venous blood which can be used for lactate measurement: peripheral venous blood, central venous blood and mixed venous blood.

This second of two articles on understanding the clinical value of measuring urea concentration explores the clinical value of simultaneous measurement of urea and creatinine and calculating the urea:creatinine ratio. The article discusses the causes of increased and decreased ratio as well as the clinical application ...

This first of two articles on understanding the clinical value of measuring urea concentration dives into the physiological topics, such as urea production and renal processing of urea as well as the causes of increased and reduced urea concentration. Kidney disease is associated with reduced urea excretion and...

The measurement of the parameters pH, pCO₂ and pO₂ is vulnerable to a number of preanalytical errors and this article shares practical tips to help avoid these errors, ensuring that the results of analysis accurately reflect the patient’s acid-base and oxygenation status. The tips include the removal of air bubbles, ...

The process of blood gas and pH measurement involves preheating the arterial blood sample to normal body temperature (37 °C) prior to measurement of pH, partial pressure of oxygen (pO₂) and partial pressure of carbon dioxide (pCO₂). This ensures that results reflect in vivo temperature condition. A minority of...