The blood glucose meter device is electronic hardware and does not have a traditional expiration date like food or medication. The meter is designed to function for many years, often lasting up to a decade. Manufacturers often suggest replacement every few years due to technology advancements or wear and tear. The device usually becomes obsolete or fails mechanically long before any fixed expiration date is reached. Confusion about device expiration stems from the sensitive, short-lived chemical components the meter relies on for accurate readings.
The Components That Require Expiration Monitoring
The true expiration concern lies with the accessories and consumables necessary for testing, primarily the test strips and control solutions. Test strips are coated with specific organic enzymes, such as glucose oxidase, that react with the glucose in a blood sample. This reaction converts the glucose concentration into an electrical current the meter reads, but these enzymes degrade over time.
Test strips carry an expiration date printed on the box or vial, guaranteeing accuracy before the enzymes lose effectiveness. Once a vial is opened, there is a “use within” date, typically three to six months, regardless of the printed expiration date. Exposure to air and moisture accelerates the breakdown of the chemical reagents, so the vial must be tightly sealed after each strip is removed.
Control solutions are liquid mixtures used to check if the meter and strips are working correctly. These solutions have two expiration dates: the sealed bottle date and a shorter discard date, often three months, after opening. Since the solution’s integrity is easily compromised once exposed to air, users should write the opening date directly on the bottle. Lancets are sterile needles used to prick the finger and have an expiration date related to sterility.
Impact of Expired Materials on Reading Accuracy
Chemical degradation in expired test strips directly compromises the accuracy of the blood glucose reading. The enzymes on the strip surface, which initiate the electrochemical reaction with blood glucose, become less reactive or inactive. When the meter measures glucose concentration based on a weakened chemical signal, it produces a result that does not accurately reflect the actual blood sugar level.
This failure can lead to dangerously misleading readings, which may be falsely high or falsely low. A false high reading might prompt a patient to administer an unnecessary dose of insulin, potentially causing hypoglycemia. Conversely, a false low reading could result in a missed dose of insulin, leading to hyperglycemia or diabetic ketoacidosis.
Because these inaccuracies risk mistakes in treatment decisions, manufacturers advise against using any component past its expiration or discard date. If a user suspects an issue with their strips, they should use a control solution test to verify the system’s performance. This liquid contains a known glucose concentration, and if the meter reading falls outside the specified range, it confirms the meter or the strips are not functioning reliably.
Extending the Functional Life of the Meter
While the meter does not expire, proper maintenance ensures its functional life and reading reliability. The internal electronics are sensitive to environmental conditions. The device should be stored at room temperature, away from extremes of heat or cold. High humidity or direct sunlight can cause damage and shorten the meter’s working life.
Regular maintenance helps prevent measurement errors. The test strip port and the exterior should be kept clean, as debris or dried blood can interfere with the strip insertion and the electrochemical process. Manufacturers recommend wiping the meter with a soft, damp cloth, avoiding harsh chemical cleaners that could damage the casing.
Consistent power supply is important for the meter to perform its calculations correctly. Users should pay attention to the low battery indicator and replace batteries promptly. Low battery power can lead to inconsistent or inaccurate readings.