Therapeutic impact of routine electrolyte testing in childhood diarrhoea.

Aim: To report on the management of plasma sodium and potassium disturbances, identified by routine electrolyte testing in children.

Methods: A prospective cohort study of patients admitted to the Diarrhoea Rehydration Unit of Red Cross Children's Hospital, Cape Town, South Africa. The patients were 530 children aged 6 weeks to 2 years with a primary diagnosis of diarrhoea.

Results: For plasma sodium levels <125 mmol/L (3.4%, 95% CI 2.0-0 5.3), 48 patients (95% CI 30-116) needed testing for one to receive a change of management. For plasma potassium levels <3 mmol/L (31.6%, 95% CI 27.6-35.6), fewer patients (6, 95% CI 5-7) needed testing for one to receive a change of management.

Conclusion: Electrolyte abnormalities were detected and clinical management changed, but large numbers of patients needed to be tested for each change of management.