The serum (plasma) anion gap is a useful additional piece of clinical information that can be easily derived without cost from the results of the most commonly requested biochemical profile, urea and electrolytes (U&E). It is the difference between the sum of measured anions (chloride and bicarbonate) and the sum of...

Diabetic ketoacidosis (DKA) is a life-threatening acute metabolic disturbance that results from absolute or relative insulin deficiency. It is usually precipitated by intercurrent illness and is a relatively common complication of type 1 diabetes but only rarely occurs in those suffering type 2 diabetes.  The cardinal ...

Critical values are those associated with imminent danger unless acted upon promptly. Critical value menus often include results that do not fit this definition, leading to highly variable practice in adult and pediatric laboratories. Existing menus may be subdivided into more uniform tiers of severity: the highly...

No history of the development of blood gas analysis and its application in clinical and physiology research would be complete without consideration of the pioneering work of anesthesiologist researcher Dr John Severinghaus.  As a young research fellow in the 1950s he developed the Stow-Severinghaus-type carbon dioxide ...

As a global marker of tissue oxygenation serum lactate measurement has proven its usefulness in monitoring the critically ill. It has also proved useful as a screening tool for sepsis in the emergency room.  However, lactate measurement is not always readily available. Increased lactate is a common cause of raised...

Traditionally, interpretation of blood gas results for the assessment of acid-base status has been based on the Henderson-Hasselbalch equation, the central focus of which is the carbon dioxide – the bicarbonate buffer system. At its most reduced form the equation can be stated as “pH is proportional to the ratio of...

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...

The field of point-of-care testing (POCT) is entering a period of rapid expansion. This expansion is being driven by new evidence for clinical effectiveness of POCT, and new technologies that allow consolidation of testing onto smaller platforms. Technological improvements will also lead to increased accuracy for...

 Of all tests performed on patient blood samples, arterial blood gases (ABGs) are conceptually probably the most complex. An understanding of the clinical significance of the measured and derived parameters generated by blood gas machines depends on a basic knowledge of so many topics, including acid-base theory,...