November 13, 2013

Blood Glucose Test Strips, Coding

One of the questions I have needed to research the last few weeks arrived in the month of August and asked why each vial of test strips had a code that needed to be entered into the meter. I knew this was true, but not a question I had all the answers to or the reasons behind this requirement. Then the question expanded to meters not requiring coding and why. This I did know, but I will cover that later in the blog.

Each test strip manufacturer has a proprietary method of coding to match the test strip to the meter. This is their method of making sure that other test strips are not to be used with their meter. This is also the reason you are told to use the container the batch came in until the test strips are used up to 1) not ruin the strips and 2) confuse different batches with different codes.

To cover as many meters as possible, the following are some of the reasons for the coding:

#1. For some meters and testing strips, the vial comes with a “code key” that you insert into the meter. This key automatically codes the meter to the strips you are using from that container. When you start a new container of test strips, you recode the machine using the new “code key” you receive with that container of test strips.

#2. Some meters require that you manually change the code to match the number on the container of test strips. Generally, for these meters, press and hold the "C" button until the correct number shows on the screen, then release the button. Your glucose meter is now coded for the container of test strips you are now going to use.

#3. With many of the newer meters, the meter will code itself immediately upon insertion of a test strip. This eliminates the need for a code key or manual re-coding of your meter. The test strip has the code embedded in the strip for the meter to read when it is inserted.

#4. Often these codes or other information (often alphanumeric combinations) on the box with the test strip container is used if a recall of test strips is made.

What is coding and what are the purposes of coding?

Several years ago, I remember that there was an article discussing this and if I remember correctly, coding was used to correct testing accuracy. If a batch of test strips were reading outside the acceptable range, such as 15% too high from the standard, then coding would correct for this and subtract the 15% to give the correct reading.

Now some of the manufacturers have moved to no coding required because the coding chip is in the test strip. This means that the strip is automatically adjusted to the meter for accuracy by checking the strip electronically.

Blood glucose test strips are a part of life for people with diabetes. These tests strips are available online from many companies. The newest ones normally do not require coding, but the older ones would still require patients to understand codes and code the meter to obtain accurate results.

The greatest problems with coding the meter are:
#1. User forgets to recode the meter when using a new vial of test strips, and
#2. The user enters the incorrect code.

Then the problems can begin when the accuracy is compromised. Generally, the incorrect code means the risk of hypoglycemia increases because the insulin dose was too high. Seldom the reverse can happen and hyperglycemia results. Either way the risks have increased and this is the main reason to not use the meter and test strips requiring coding. I have no problem with the code key, but even then, errors can be made.

Other interesting blogs you may enjoy reading include this one and this by David Spero. Then David Mendosa has this blog on operator errors on Health Central.

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