The calcium present in blood plasma comprises two almost equal fractions: half is bound to albumin and the remainder is unbound, free ionized calcium. Only the free ionized calcium is physiologically active. There are two ways of assessing patient blood calcium status.  The first – at one time the only available...

Arterial blood gas analysis in cases of metabolic acidosis reveals primary decrease in pH and bicarbonate, and secondary (compensatory) reduction in pCO₂. The most common cause of metabolic acidosis is increased production of endogenous metabolic acids, either lactic acid, in which case the condition is called lactic...

Clinical biomarker studies seldom follow recommendations for the evaluation of new biomarkers. Therefore it is important to assess any published clinical value of a biomarker or comparison of two or more biomarkers and see whether or not the published study applies to your situation. If the published study does not...

The preanalytical phase of laboratory testing has long been recognized as a stage for potential error, and blood gas analysis is a test that is well-recognized as being particularly vulnerable in this regard. Much research has been directed at devising procedures that minimize variability of measured blood gas...

In health, plasma potassium concentration is maintained within the approximate range of 3.5-5.0 mmol/L. Hypokalemia, a very common electrolyte disturbance – present in up to 20 % of hospitalized patients – is diagnosed if plasma potassium is less than 3.5 mmol/L.  Although mild hypokalemia is often asymptomatic, a...

Metabolic acidosis is a common metabolic disturbance among the acutely/critically ill that has many possible causes. The condition is diagnosed by arterial blood gas analysis which reveals primary reduction in pH and bicarbonate, followed by secondary (compensatory) reduction in pCO₂.  Abnormal accumulation of...

Compared with other plasma electrolytes, such as sodium, potassium and bicarbonate, chloride usually gets very limited coverage in medical texts. Now in a wide-ranging review article chloride gets the exclusive billing that its physio-pathological significance deserves.  The article begins with consideration of the...

Blood gas analysis is unique among blood tests in its requirement for arterial blood; all others are performed on venous, or more rarely, capillary blood samples. Sampling arterial blood is a technically difficult procedure to perform, and painful for the patient: significantly more painful than sampling either venous ...

When collecting blood for blood gas analysis, it is important to remove air bubbles from syringes to avoid erroneous results, especially for pO₂, with a number of factors affecting the potential magnitude of the interference to pO₂ by air bubbles.  In this study, we calculate the expected theoretical changes in pO₂...

Reprinted and translated by permission of Läkartidningen from “Serumlaktat - användbar analys inom akutsjukvården”, by Bengt R Widgren and Monique Ekhardt, 2011; vol 108: 475-477. Copyright 2011 by Author, Läkartidningen and AB Typoform, Sweden.Translated by Radiometer Medical ApS. In emergency care triage, diagnosis...