The Accuracy of Point-of-Care Creatinine Testing in the Emergency Department

Abstract

Objective. To determine the accuracy of Point-Of-Care testing (PoCT) creatinine values when compared to standard central laboratory testing (IDMS) and to demonstrate if and how a discrepancy could lead to improper risk stratification for contrast induced nephropathy (CIN). Methods. We conducted a descriptive retrospective chart review of patients seen in the Emergency Department of a single suburban, community, and academic medical center. We included patients who presented to the department between March 2013 and September 2014 who had blood samples analyzed by both PoCT and IDMS. Results. Mean IDMS creatinine values were 0.23 mg/dL higher when compared with i-Stat values. 95% of the time, the IDMS creatinine value was variable and ranged from −0.45 mg/dL to +0.91 mg/dL when compared to the i-Stat creatinine. When using i-Stat creatinine values to calculate GFR, 47 out of 156 patients had risk category variations compared to using the IDMS value. This affected 30.1% of the total eligible sample population (22.9% to 37.3% with 95% CI). Conclusion. We found a significant discrepancy between PoCT and IDMS creatinine values and found that this discrepancy could lead to improper risk stratification for CIN.