The ‘gold standard’ sample for blood gas analysis is arterial blood obtained via an indwelling arterial catheter or by arterial puncture. For a number of reasons capillary blood is an attractive substitute sample that is routinely used in some clinical settings.  The purpose of this article is to examine the evidence ...

There are few medical diagnoses that depend solely on the result of a single blood test, but diabetes mellitus, which is defined by concentration of circulating glucose, is one that does. Quite apart from its long established role in diagnosis as well as life-long monitoring of diabetes, measurement of circulating...

Modern analytical devices for testing biological fluids, such as blood, have now developed a sophistication that ensures the quality of the analytical result is capable of matching that achieved in the central laboratory.    Complementary developments are focused on reducing operator-related and connectivity-related...

The integrity and function of all cells depend on an adequate supply of oxygen. Severe acute illness is frequently associated with inadequate tissue perfusion and/or reduced amount of oxygen in blood (hypoxemia) leading to tissue hypoxia.  If not reversed, tissue hypoxia can rapidly progress to multiorgan failure and ...

Homeostatic mechanisms ensure that in health the extracellular fluid (ECF) concentration of electrolytes, including calcium, is maintained within well-defined limits. Abnormality in ECF calcium concentration can have profound adverse effects.  The most common means of assessing calcium status is to measure total...

The significance of good practice during the pretesting phase of clinical laboratory investigation cannot be  overemphasized. The production of high-quality, accurate results which are clinically useful depends as much on practice before the patient’s sample reaches the laboratory as it does on the analytical phase...

Measurement of plasma/serum sodium concentration is one of the most frequently requested blood tests in clinical practice. Although usually performed in the laboratory, the test is also available at the point of care using technology incorporated into blood gas and other point-of-care analyzers. In health, sodium...

The principal function of the protein hemoglobin contained in red blood cells is transport of oxygen in inspired air from lungs to tissue cells. Although normally present in only trace amounts, there are three species of hemoglobin that cannot transport oxygen. The three species, collectively called the dyshemoglobins ...

This is the second of two articles about the risks and benefits of red-cell transfusion directed at healthcare professionals without any particular transfusion expertise. The focus of the first article was the risks and the extensive measures taken to minimize those risks. For this second article, attention turns to...

Although often of life-saving benefit, transfusion of donated red cells is associated with considerable potential risk for the recipient patient. This article, directed at healthcare professionals without any particular transfusion expertise, outlines these risks and the measures taken to minimize them. Particular...