BLOOD GLUCOSE TEST STRIPS - PART II - The EBGTS story!

Electrochemical blood glucose test strips (EBGTS)

The electrochemical blood glucose test strip (EBGTS) is a very small volume (often about one µl or less) disposable electrochemical cell, which is contacted with whole blood. It then produces, in conjunction with a test meter, an electrical current which is proportional to the blood glucose concentration. Typical currents are a few µA.

This electrical current is produced by the very selective oxidation of glucose in the blood sample, which is catalyzed by two reagents which are precoated inside the test strip: 

(i) an enzyme, which reacts directly with the glucose molecule to remove its two available electrons, and 

(ii) a mediator molecule, which takes (either singly or as a pair) the two electrons from the enzyme, and transports them to the working electrode, where they can be measured. 

This process is illustrated in Figure below.

Electrons flow from glucose to an enzyme to a redox mediator to the working electrode.


The enzyme and mediator act as a sort of electron bucket brigade to transport electrons from glucose to the working electrode. Each enzyme and mediator molecule can repeat this transfer again and again, if necessary. There are a wide variety of different enzymes and mediators which are suitable for use in an EBGTS. Although there are many differences between the various commercially available test strips, they all rely on the fundamental mechanism 


Copied by permission from the "Electrochemistry Dictionary" (http://electrochem.cwru.edu/ed/dict.htm) on "04/09/12." The original material is subject to periodical changes and updates.