Evaluating the Utility of Rapid Point-of-Care Potassium Testing for the Early Identification of Hyperkalemia in Patients with Chronic Kidney Disease in the Emergency Department

PURPOSE Severe hyperkalemia leads to significant morbidity and mortality if it is not immediately recognized and treated. The concentration of potassium (K⁺) in the serum increases along with deteriorating renal function. The use of point-of-care K⁺ (POC-K⁺) in chronic kidney disease (CKD) could reduce the time for an accurate diagnosis and treatment, saving lives. We hypothesized that POC-K⁺ would accurately report K⁺ serum level without significant differences compared to reference testing, regardless of the renal function of the patient. MATERIALS AND METHODS The retrospective study was performed between January 2008 and September 2011 at an urban hospital in Seoul. The screening program using POC was conducted as a critical pathway for rapid evaluation and treatment of hyperkalemia since 2008. When a patient with CKD had at least one warning symptom or sign of hyperkalemia, both POC-K⁺ and routine laboratory tests were simultaneously ordered. The reliability of the two assays for serum-creatinine was assessed by intra-class correlation coefficient (ICC) analysis using absolute agreement of two-way mixed model. RESULTS High levels of reliability were found between POC and the laboratory reference tests for K⁺ (ICC=0.913, 95% CI 0.903-0.922) and between two tests for K⁺ according to changes in the serum-creatinine levels in CKD patients. CONCLUSION The results of POC-K⁺ correlate well with values obtained from reference laboratory tests and coincide with changes in serum-creatinine of patients with CKD.