The process of patient sample testing, whether performed in the clinical laboratory or at the point of care, is the sum of three distinct phases. The first is the preanalytical phase, which includes test selection as well as sample collection and handling.  The second is the analytical or measuring phase that...

Clinical laboratory measurement of serum/plasma creatinine concentration has been used to assess patient kidney function for well over 50 years.  With the incorporation of creatinine analyses to blood gas and other point-of-care platforms the test is now available outside the laboratory, at the bedside and in the...

Clinical laboratory measurement of serum/plasma creatinine concentration has been used to assess patient kidney function for well over 50 years. With incorporation of creatinine analyses to blood gas and other point-of-care platforms the test is now available outside the laboratory, at the bedside and in the clinic.  ...

One of the principal utilities of arterial blood gas (ABG) analysis is to help assess blood oxygenation status. The two ABG parameters used for this assessment are pO₂(a) (partial pressure of oxygen in arterial blood) and sO₂(a) (% of total hemoglobin that is saturated with oxygen). In health pO₂(a) is maintained...

Pleural effusion, defined as excess fluid in the pleural space, can complicate the course of a large and pathologically diverse range of pulmonary and non-pulmonary diseases. Laboratory analysis of pleural fluid provides much useful information for the clinician whose diagnostic challenge is the patient presenting...

The anion gap (AG) is a calculated parameter derived from measured serum/plasma electrolyte concentrations. The clinical value of this calculated parameter is the main focus of this article. Both increased and reduced anion gap have clinical significance, but the deviation from normal that has most clinical...

This is the second of two articles focusing on the reference interval, the most widely used tool for interpretation of patient test results.  The first [1] was an introduction to the theoretical concepts that underpin the significance, construction and use of reference intervals. Here consideration is given to the...

The population-based reference interval is the most widely used tool for interpretation of individual patient laboratory test results. The clinical value of those results depend crucially on the reference intervals with which they are compared, and all efforts directed at ensuring analytically precise and accurate...

Updated with new information from a 2008 article! Health demands that despite quite significant variation in its rate of production, the amount of carbon dioxide in blood is maintained within well-defined narrow limits. The homeostatic mechanisms that maintain the normal content of carbon dioxide in blood are...

All clinical procedures and treatments are associated with potential adverse effects of greater or lesser significance.  The undisputed value of blood testing for both diagnosis and monitoring of disease is tempered by the recognition that repeated blood sampling can result in blood loss of sufficient magnitude to...