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...

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...

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 ...

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...

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...

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...

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,...

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...

Unless suffering some unrelated acute/critical illness, diabetic patients are only usually submitted for arterial blood gas analysis if they are suspected of suffering diabetic ketoacidosis, the potentially life-threatening acute complication of diabetes that is almost invariably associated with severe hyperglycemia....

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...