Validity of the <i>International Classification of Diseases, Tenth Revision</i> code for acute kidney injury in elderly patients at presentation to the emergency department and at hospital admission

Patients with hospital encounters who were ICD-10 E87.5 hyperkalaemia code positive and negative had distinct higher and lower serum potassium values, respectively. However, due to very low sensitivity, the incidence of hyperkalaemia is underestimated.