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...

Serum sodium concentration is normally maintained within the approximate reference range of 135-145 mmol/L.Abnormal sodium concentration (dysnatremia), which is a relatively common feature of critical illness – affecting 10-20 % of intensive care patients – is associated with adverse outcome for this patient group....

Diabetic ketoacidosis (DKA), which is an acute, potentially life-threatening complication of poorly controlled diabetes, is the subject of a recent comprehensive review article.   The authors discuss epidemiological issues, revealing increasing incidence of DKA and decreasing mortality.  Once inevitably fatal, DKA...

In regulating blood bicarbonate concentration the kidneys play a central role in acid-base homeostasis, and severe renal failure causes metabolic acidosis. This is a disturbance of acid-base characterized by primary reduction in blood bicarbonate and pH, and secondary (compensatory) decrease in pCO₂. One of the aims...

Phototherapy, the standard treatment for neonatal jaundice, is guided by age-related serum bilirubin concentration; the older the baby, the higher is the recommended triggering serum bilirubin concentration. So that for example, UK guidelines state that for a full-term baby who is 12 hours old, phototherapy should be ...

Three parameters generated during blood gas analysis, pH, pCO₂ and bicarbonate, provide the means for assessment of patient acid-base status, which is frequently disturbed in the acutely/critically ill. Four broad classes of acid-base disturbance are recognized: metabolic acidosis, respiratory acidosis, metabolic...

For patients presenting to the ED with symptoms of a suspected infection, measuring procalcitonin (PCT) is a useful diagnostic tool to identify bacterial infections, such as sepsis, allowing for early initiation of proper antibiotic treatment. In assessing the severity of sepsis, serum PCT levels are an important...

This first of two articles on method comparison studies gives some key concepts related to the design of the method comparison study, data analysis and graphical presentation, stressing the importance of a well-designed and carefully planned experiment using adequate statistical procedures for data analysis when...

When a new D-dimer method is evaluated, it’s typically compared to an established D-dimer method using both an analytical and a clinical comparison. Analytical comparisons should be discouraged, as they do not give any useful information about the potential clinical usability of the assay. D-dimer assay comparisons...

Blood gas analysis provides the means for assessing patient oxygenation status by measurement of two parameters: the partial pressure of oxygen in arterial blood (pO₂(a)) and % oxygen saturation of hemoglobin in arterial blood (sO₂(a)). Most accurate reflection of in vivo pO₂(a) and sO₂(a)  requires that measurement...