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

Abstract

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.