This second of two articles on understanding the clinical value of measuring urea concentration explores the clinical value of simultaneous measurement of urea and creatinine and calculating the urea:creatinine ratio. The article discusses the causes of increased and decreased ratio as well as the clinical application ...

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...

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...

Barnsley Emergency Department (ED), which recruited patients into the RATPAC trial, initiated a point-of-care (POC) pathway for low-risk chest pain patients from December 2011. All patients who underwent POC testing for chest pain between December 2011 and July 2012 were identified. Patient notes were then examined...

Point-of-care pathology testing is becoming increasingly common in hospitals, clinics and doctors’ offices; anywhere where time is critical and results are required at the patient’s side.  However, results must be accurate and reproducible to be meaningful, and it is imperative that a close eye is kept on...