Central laboratory or point-of-care testing of blood to determine natriuretic peptide (either BNP or N-terminal proBNP) concentration has a clinically established role in the differential diagnosis of patients presenting with breathlessness; normal levels exclude a diagnosis of heart failure, a common cause of...

Potassium, the most frequently measured electrolyte in clinical practice is, in health, maintained at a blood serum concentration within the approximate reference range of 3.5 to 5.2 mmol/L. Physiological control of this potassium concentration depends crucially on the ability of the healthy kidney to regulate...

Clinical sensitivity, clinical specificity and predictive values are frequently used as performance measure for a biochemistry assay. When D-dimer assay performance is presented, emphasis is often on the negative predictive value (NPV). However, predictive values are greatly influenced by the prevalence of the...

With the ultimate goal of improving patient care, adoption of point-of-care testing (POCT) continues to grow at a high rate. The ability to deliver fast and reliable results near the patient is a key driver for improving patient outcomes and optimizing clinical workflow. While there are many advantages, controlling...

Plasma sodium concentration is measured with an ion-specific electrode (ISE) using either an undiluted sample (direct ISE) or diluted sample (indirect ISE).  This is the second of two linked articles highlighting the spurious sodium values that can occur if an indirect ISE method is used to analyze plasma samples with ...

Reprinted from Ann Lab Med 2014 Sep; 34(4):263-73. Procalcitonin (PCT) is used as a biomarker for the diagnosis of sepsis, severe sepsis and septic shock. At the same time, PCT has also been used to guide antibiotic therapy. This review outlines the main indications for PCT measurement and points out possible...

This article first appeared in Pathology in Practice (Hobba H, Silver L. Evolution of POC testing. Pathology in Practice 2013; 14 [2]: 63) and is reproduced here by kind permission (www.pathologyinpractice.com). © 2013 kdm communications limited Point-of-care (POC) testing has allowed the pathology department in...

Blood glucose concentration is normally maintained within the approximate range of 3.5-8.5 mmol/L (63-153 mg/dL) largely by the synergistic opposing action of two pancreatic hormones: insulin and glucagon. Insulin secretion causes decrease in blood glucose concentration and glucagon secretion causes increase in blood...

Arterial blood gas analysis provides the means for assessment of two related physiological functions that are disturbed in a wide range of medical conditions.  The first is the facility of the lungs to simultaneously add inspired oxygen to blood and remove carbon dioxide from blood, prior to excretion in expired air...

Lactic acidosis, the most common kind of metabolic acidosis, is characterized by reduced blood pH (usually <7.25) in association with marked increase in blood lactate (usually >5.0 mmol/L). Lactic acidosis has many possible causes but two broad etiological classes have been defined: type A (hypoxic) lactic acidosis and ...