Computer based audit of potassium monitoring

We conducted a computer-based audit of serum potassium monitoring at a university teaching hospital over the course of a single year. Intensive monitoring accounted for half of 59,488 potassium determinations performed by the laboratory. Strong preferences were shown for monitoring at intervals of 4, 12, 24, and 48 hours. Individual patients tended to be tested at the same interval repeatedly; the time separating two potassium determinations was significantly correlated with the time separating the previous two determinations (R² = 0.3; P < 0.0001). The rate at which potassium was monitored was not strongly correlated with the presence of severity of potassium abnormalities revelaed in previous determinations; the coefficient of determination (R²) ranged from 0 to 0.06 for six different types of potassium abnormalities examined. These observations suggest that potassium monitoring accounts for a substantial proportion of all potassium testing and that monitoring is not being used to follow preexisting potassium abnormalities. Potassium monitoring is conducted according to fairly rigid testing protocols. However, the selection of a particular protocol may be difficult to explain with a computer-based audit focused on laboratory data.