Four Key Technical Elements
FreeStyle® systems offers the combination of four key technical elements: Coulometry, Reliable Sample Detection, Glucose Dehydrogenase, and Low Potential (Voltage) Measurement.
In fact, FreeStyle systems are the only systems to have all four technical elements and provide outstanding clinical accuracy and precision. The state of the art technology minimizes influences from many of the common factors affecting clinical results.
While most blood glucose monitoring systems use other technologies, which measures only a fraction of the glucose reaction signal in a blood sample, FreeStyle systems uses a technology based on coulometric measurement. Coulometry is a unique, patented, electrochemical measurement technique employed exclusively in FreeStyle technology. The benefit of the coulometric analysis is that it is unaffected by reaction rates.
It is an ideal technique for measuring a small sample size since the total accumulated charge is used to calculate glucose concentration. In fact, FreeStyle systems require the world’s smallest blood sample, just 0.3 microliter. Most leading meters use other technologies for glucose measurement, which are more challenging to adapt to smaller blood sample requirements.
Reliable Sample Detection
Reliable sample detection is an important element for system accuracy. Blood testing procedures for modern glucose meters are simple, but application of an adequate blood sample to the test strip is necessary for accurate measurements. FreeStyle systems have the ability to detect an adequate sample.
The difference between FreeStyle systems and systems without reliable sample detection is that the FreeStyle meters do not report a result when an insufficient sample is applied to the test strip. When a sufficient sample is applied, a correct result is obtained.
The test strip uses capillary action and acts like a sponge to "pull" the exact amount of blood (0.3 microliter) into the test strip. If not enough blood fills the test strip area and nothing happens, the user has up to 60 seconds to add more blood to the same sample area of the test strip.
If enough blood fills the test strip sample chamber, the meter then “beeps” indicating there is sufficient blood and begins the test.
Glucose Dehydrogenase (GDH)
A key contributor to the accuracy of FreeStyle systems is the unique enzyme and mediator combination used in the test strip. The enzyme used in the FreeStyle test strip is called Glucose Dehydrogenase (GDH). This enzyme can be used to perform electrochemical glucose measurements without interference by oxygen in the blood sample.
The commonly used enzyme in most other electrochemical strips, Glucose Oxidase (GOX), is capable of reacting with oxygen to produce interference in the measurement.
Low Potential (Voltage) Measurement
Low Potential Measurements offer a method for minimizing the interference by substances present in blood. In order for an electrochemical reaction to occur, a potential (voltage) must be applied between a working and counter electrode. The larger the applied potential, the greater the number of interfering substances that can react and produce a signal. The proprietary osmium based mediator used in the FreeStyle test strip allows the glucose reaction to occur at a low potential.
For this reason, very few substances can interfere with the FreeStyle system readings. Unlike strips that use iron-based mediators, the FreeStyle strip minimizes the effects of interfering agents such as uric acid, aspirin and acetaminophen (at elevated levels).