• hyponatraemia
• syndrome of inappropriate secretion of antidiuretic hormone
• clinical biochemistry
• chemical pathologist

Hyponatraemia is probably the most common electrolyte disturbance encountered in clinical practice. Despite this, the best way to manage this condition is debated and not always fully appreciated. Indeed, there may be problems in both the investigation and its treatment, as is highlighted in the paper by Saeed and colleagues in this month’s edition.¹

One problem would seem to be that some clinicians experience difficulties in investigating the causes of hyponatraemia. It is here where the clinical biochemistry laboratory and chemical pathologist can play an important role in facilitating optimal patient care. Interestingly, Saeed and colleagues showed that rarely did patients with severe hyponatraemia have their urine osmolality or sodium checked.¹ In such cases, it is difficult to see how the cause of the hyponatraemia could be clearly established. This of course …