Blood test strips are small, yet sophisticated tools used with a glucose meter to measure blood sugar levels. These strips are crucial for individuals managing conditions such as diabetes, enabling them to monitor their glucose concentrations regularly. Each strip contains a chemical system designed to react with the glucose in a blood sample, providing a reading that helps guide health management decisions.
Diminished Accuracy Over Time
Expired blood test strips are generally not accurate for monitoring blood glucose. Their reliability diminishes because the delicate chemical components within the strip degrade over time. This degradation is not a gradual, predictable decline; instead, it can lead to significant and variable inaccuracies in readings. Manufacturers place expiration dates on the packaging, indicating the period during which the strips provide accurate results. Using strips beyond this date increases the likelihood of receiving faulty information.
Factors Causing Loss of Accuracy
The loss of accuracy in blood test strips primarily stems from the degradation of their enzymatic and chemical components. Test strips typically contain an enzyme, such as glucose oxidase, which reacts specifically with glucose in the blood. This enzyme converts glucose into gluconic acid and hydrogen peroxide, generating an electrical current that the meter reads. Over time, and particularly when exposed to certain environmental conditions, this enzyme can break down and lose its effectiveness. Environmental factors significantly accelerate this chemical breakdown. Heat, humidity, light, and air exposure can compromise the strip’s ability to react correctly. For instance, high temperatures can denature enzymes, while excessive humidity degrades chemical integrity. Leaving a vial uncapped exposes strips to air and moisture, leading to rapid deterioration and inaccurate results.
Risks of Using Expired Strips
Relying on inaccurate readings from expired blood test strips can lead to serious health complications. For individuals managing diabetes, precise blood glucose monitoring is essential for making informed decisions about medication dosages, particularly insulin. An incorrect reading, whether falsely high or low, can result in the administration of an inappropriate amount of insulin, potentially leading to dangerous health events. For example, a falsely low reading might cause someone to take too little insulin, leading to hyperglycemia (high blood sugar), which can result in conditions like diabetic ketoacidosis if left untreated. Conversely, a falsely high reading might prompt someone to take too much insulin, risking hypoglycemia (low blood sugar), characterized by symptoms such as shakiness and confusion, and in severe cases, seizures or loss of consciousness.
Maintaining Test Strip Reliability
Ensuring the reliability and accuracy of blood glucose testing involves several practical measures. Adhere strictly to the expiration date on the test strip packaging, as this guarantees chemical stability. Once a vial is opened, note the date and discard remaining strips after the typical three to six-month usage period.
Proper storage conditions are also necessary to preserve strip integrity. Keep test strips in their original, tightly sealed container, away from direct sunlight, extreme temperatures, and high humidity, such as bathrooms or kitchens.
Handle strips with clean, dry hands, removing only one at a time just before use to prevent contamination. Expired test strips should be properly discarded according to local guidelines for medical waste disposal.