Studi Komparabilitas Sistem POCT Glukosa Amperometrik terhadap Metode Heksokinase Chemistry Analyzer Berdasarkan Protokol CLSI EP15-A3

Abstract

Blood glucose monitoring requires rapid and accurate analytical instruments. Amperometric biosensor-based glucose Point-of-Care Testing (POCT) is widely utilized due to its operational efficiency; however, its accuracy and analytical comparability remain scrutinized when compared to central laboratory reference methods. This study aims to evaluate the analytical comparability of an amperometric glucose POCT system against the reference Hexokinase method on an automated Chemistry Analyzer using the CLSI EP15-A3 protocol framework. This method comparison study evaluated 40 patient blood samples collected via consecutive sampling from outpatient and inpatient settings. Statistical analyses included linear and Deming regression (with 95% Confidence Intervals), Bland-Altman difference plots, and Medical Decision Chart visualization based on Six Sigma metrics with Total Allowable Error (TEa) thresholds of 10% (CLIA 1988) and 8% (CLIA 2024). Regression analysis revealed a strong linear association with the equation y = 0.9372x + 10.957 (R² = 0.9915). Nevertheless, high correlation does not infer method interchangeability. Bland-Altman plot analysis identified constant and proportional errors, alongside significant negative bias trends at lower glucose concentrations. Evaluation via the Medical Decision Chart demonstrated that at Medical Decision Concentration (MDC) 1 (low glucose, 45 mg/dL), the POCT system exhibited a systematic bias of 18.07%, imprecision (%CV) of 2.3%, and Total Error of 22.58% (exceeding TEa 10%), yielding a performance metric of -3.5 Sigma (unacceptable method performance). Conversely, at MDC 2 (120 mg/dL) and MDC 3 (180 mg/dL), the system achieved performance ratings of 3.4 Sigma and 5.4 Sigma, respectively (acceptable to excellent performance). In conclusion, while the amperometric glucose POCT system is reliable for monitoring normoglycemic and hyperglycemic states, it presents critical analytical bias risks during hypoglycemia, necessitating verification by central laboratory hexokinase methods in critical clinical scenarios.

Keywords:       Amperometry, Bland-Altman, CLSI EP15-A3, Hexokinase, Laboratory Quality, Medical Decision Chart, POCT, Six Sigma Metrics