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...

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...

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 ...

Frequent blood glucose measurement is one element of the routine intensive monitoring that all critically ill patients receive following admission to intensive care units. Transient increase in blood glucose concentration (hyperglycemia) is very common in this patient group.  The significance of this so called stress...

Arterial blood gases are frequently useful in the clinical management of patients with chronic obstructive pulmonary disease (COPD) to assess both oxygenation and acid-base status.   A recent review article focuses on disturbance of acid-base in these patients, which occurs in advanced disease when pulmonary gas...

Around 25 % of blood samples recovered from patients admitted to intensive care and 8 % of those recovered from all other hospitalised patients would return a plasma sodium result 4-10 mmol higher than its true value if the method of analysis was indirect ion selective electrode (ISE). This is the headline finding of...

The anion gap (AG) is a calculated parameter derived from measured plasma electrolyte concentrations that is most frequently used to elucidate acid-base disturbances in the critically ill. It is defined as the difference between measured anions and cations in blood plasma and is calculated by subtracting the sum of...

According to the authors of a recently published study little is known of the clinical effects of abnormal plasma chloride concentration among the critically ill. Their retrospective study illuminates this apparent grey area of clinical knowledge.  The study involved retrieval and analysis of laboratory data,...

Clinical laboratories usually have a policy for repeat testing when the test result is either grossly abnormal or unexpected in terms of recent validated test results for that particular patient. The rationale for this policy is that the first test result may represent a clinically significant analytical error, which...

A significant increase in the use of blood tests for the management of trauma patients has had little overall effect in terms of survival following trauma, or the length of time those who survive have to spend in hospital.  This is a headline finding from a recently published study examining the clinical impact of...