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How do diabetes test strips work?

diabetes test strips


What are test strips?

The test strips are, together with the glucometer, one of the essential elements for self-monitoring and management of diabetes.

Currently, there are several ways to measure glucose, although the most common is still through test strips and glucose meters. Although in Solutions for Diabetes, we have talked about other systems, such as continuous monitoring systems, which do not require pricks as they do not measure blood glucose, capillary measurement is the most reliable and is used to obtain more accurate results.

Test strips are a recent invention (mid-twentieth century), and there are different types to make different measurements. We will focus on glucose test strips, but it is good to know that they are not only used for these types of tests but are also useful for measuring other parameters.

This implies that not all measurements are made in blood. We can also obtain results through other fluids, such as urine.

How do test strips work?

Test strips, often used in medical or chemical analysis, operate based on the principle of reagent chemistry and colorimetric analysis. The process varies depending on what the strip is testing for (such as pH, glucose, ketones, etc.), but the basic principle is similar across different types of test strips. Here’s a general overview of how they work:

Test strips, commonly used in various fields like medical diagnostics, water testing, and urinalysis, operate on the principle of chemical reactions. Here’s a general overview of how they work:

1. Absorbent Material: Test strips are typically made of an absorbent material that holds the chemicals or reagents needed for the test. This material is often paper or a similar fibrous substrate.

2. Chemical Reagents: The absorbent material is impregnated with specific chemical reagents. These reagents are chosen based on the substance or parameter the test strip is designed to detect.

3. Sample Application: When a liquid sample (like urine, water, or blood) is applied to the test strip, it wets the absorbent material, allowing the sample to come into contact with the chemical reagents.

4. Chemical Reaction: The substance being tested reacts with the reagents. This reaction is often designed to produce a visible change, such as a color change. 

5. Interpreting Results: The result is typically read by comparing the color change on the test strip to a color chart provided with the strips. In some cases, more sophisticated devices may be used to read and interpret the results.

6. Specificity and Sensitivity: The reagents used in test strips are selected for their specificity (ability to react with a particular substance) and sensitivity (ability to detect even small amounts of the substance).

For example, in diabetes management, glucose test strips are used to monitor blood sugar levels. These strips contain enzymes that react with glucose in a blood sample, causing a color change that corresponds to the glucose level. Similarly, in aquariums, test strips are used to measure parameters like pH, ammonia, nitrites, and nitrates, each reacting differently to indicate the levels of these substances in the water.

The simplicity, speed, and relatively low cost of test strips make them a popular choice for many types of quick, point-of-use testing.

Tips for using test strips

There are some factors that can affect the accuracy of the test strips, although we must bear in mind that, as in many other systems and measurement elements, there is a small margin of error in the results.

Some of these factors are:

  • Test strip quality
  •  Storage and conservation
  •  Temperature
  •  Humidity
  •  Expiration
  •  Insufficient amount of blood on the strip

As they are items that people with diabetes can use without medical supervision (although it is recommended that a medical professional help and teach how to use them together with the chosen measuring device), we can often make mistakes in their use or storage that may affect their correct operation.

The most common mistakes are either not putting enough blood on the strip, so the result may be unreliable, or inserting the strip incorrectly into the glucometer.

It is important to keep the case or container always closed and store it in a cool and dry place with temperatures between 4º and 40º. In places with extreme temperatures, we will have to take special care with this.

To this day, test strips are used once and thrown away.

Test strips are one of the most common and important elements in diabetes self-management. As we always remember, if you have any questions or queries, the ideal is to consult with our medical professional to explain how to use them correctly. And, of course, review the leaflet that will come in the box of each product.

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