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...

Because measurements of GFR are tedious, estimated GFRs based on creatinine or cystatin C are widely used for assessing kidney function. Both measured GFRs and the Staging System for CKD based on GFR have analytical and clinical shortcomings. The advantages of serum creatinine and cystatin C, and eGFR will be...

Calculation-based approaches to determining oxygen saturation, as used in some point-of-care tests, increasingly deviate from values measured directly by CO-oximetry as the partial pressure of oxygen in the blood decreases. Oxygen saturation should be measured by CO-oximetry when inaccuracies in calculations may...

This article explores the potential benefits of point-of-care testing in the ED. Price and St. John provide a detailed description on how to approach four common aspects of point-of-care testing (POCT) in the ED, specifically, the challenges of adopting POCT, the impact of POCT on clinical decisions, the impact of...

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 a D-dimer assay in excluding venous thromboembolism (VTE) in outpatients. Together with a low pretest probability of VTE, a negative D-dimer test can rule out VTE in 30-50 % of suspected patient cases. The article highlights the importance of using a D-dimer assay with particular...

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.