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...

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...

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 ...

Disturbance of sodium balance is a common occurrence among hospitalized patients that can, if not identified and treated, cause significant morbidity; severe disturbance is potentially lethal. So estimation of plasma sodium concentration is one of the most frequently requested blood tests.  Historically, plasma sodium ...

Sampling capillary blood from the fetal scalp during labor of pregnancy, in order to determine its pH, was introduced to obstetric care in the late 1960s.  Despite current skepticism surrounding its utility, most notably in the US, fetal-scalp blood sampling (FSBS) is still considered a useful fetal monitoring test...

This short review aims to put the diagnostic options provided by state-of-the-art POCT  technology into perspective with the clinical challenges faced by physicians treating patients presenting with acute dyspnea.  Natriuretic peptides, hemoglobin, D-dimers and venous blood gases play a key role in the early...

The pH, base excess and pCO₂ (acid-base status) of arterial blood flowing through the umbilical cord provides valuable objective evidence of the metabolic condition of neonates at the moment of birth; a notion that has assured a role for the blood gas analyzer in hospital delivery suites in cases of suspected fetal...

CO-oximetry provides the means for automated spectrophotometric measurement of the concentration of total hemoglobin (ctHb) in blood and the percentages of the four hemoglobin derivatives that total hemoglobin comprises: oxyhemoglobin (O₂Hb); deoxyhemoglobin (HHb); carboxyhemoglobin (COHb); and methemoglobin (MetHb)....

Ensuring adequate oxygen delivery to tissues is a prime objective of acute/critical medical care. There is no routinely available method for directly monitoring tissue oxygenation; instead clinicians must depend on available indirect measures. Although not the only factor to be considered, measurement of the amount of ...