A clinical requirement for determination of the pH and base deficit (BD) of umbilical-cord arterial blood has ensured a role for the blood gas analyzer in the delivery suite of obstetric units.  The principal objective of this testing in the minutes immediately after birth is to identify those babies who have been...

Health demands that blood pH is maintained within narrow limits (7.35-7.45). Acidosis (i.e. pH <7.35) is a common feature of many acute/critical conditions that warrant admission to intensive care. pH <6.8 is commonly reported in medical texts as incompatible with life, but there are rare individual case reports of...

The maintenance of blood pH within normal limits (7.35-7.45), called acid-base homeostasis, is a complex synergy involving three organs (lungs, kidneys and brain) as well as chemical buffers in blood and blood cells (erythrocytes). This vital physiologic process is the subject of a recent expert review article,...

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...

The significance of good practice during the preanalytical phase of clinical laboratory investigation cannot be overemphasized. One aspect of the preanalytical phase – the transport of samples – is considered here; in particular the transport of samples via pneumatic tube systems. This is an update of a previous...

Cirrhosis of the liver is associated with increased respiration (hyperventilation) and consequent hypocapnic respiratory alkalosis. The severity of this acid-base disturbance correlates with severity of cirrhosis as well as severity of the abnormal hyperdynamic systemic circulation that characterizes this irreversible ...

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...

Health demands that the pH of blood is maintained within a narrow range (7.35-7.45). Monitoring this physiological imperative and detection of so-called acid-base disturbance, in which blood pH is either increased or decreased, is one of the principal clinical utilities of blood gas analysis.  Metabolic acidosis – one ...

Blood gas analyzers often have an incorporated CO-oximeter that allows accurate determination of carboxyhemoglobin (COHb) and methemoglobin (MetHb) from the arterial blood sample submitted for routine blood gas analysis. For patients with suspected acute pulmonary embolism (PE), arterial blood gas analysis is often...

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...