Electrochemical Interferences in Blood [Glucose Monitoring](/)

Introduction

Electrochemical interference distorts blood glucose monitoring (BGM) results. This occurs when physical properties of blood or non-glucose substances alter the electrical current measured by the test strip.

Physical Interferences

The Hematocrit Effect significantly interferes with BGM. High hematocrit levels cause false lows, while low hematocrit levels cause false highs [^hematocrit_effect]. Modern meters use AC Impedance Spectroscopy to estimate red blood cell volume and correct results algorithmically.

Chemical Interferences

Redox-active substances like Acetaminophen, Vitamin C, and Uric Acid create false positive signals [^redox_active_substances]. They oxidize at the electrode, but manufacturers counter this with low-potential mediators. These mediators, such as Osmium/Ruthenium, operate at voltages too low to oxidize contaminants.

Historical Context

GDH-PQQ strips lacked enzyme specificity, leading to fatal errors in dialysis patients due to Maltose interference [^electrochemical_interference]. This prompted an industry shift toward GDH-FAD and GDH-NAD chemistries. Glucose Oxidase (GOx) sensors must account for dissolved oxygen levels, which can skew results at high altitudes or in venous blood samples.