Learn more about blood glucose meter accuracy and why it is important.

We know that blood glucose meters are essential for managing Type 2 diabetes. How else can we track our blood sugar? Visiting the doctor every three months or so certainly isn’t the best approach, though it’s how we receive updates on our HbA1c. Blood glucose meters are also used to monitor our progress on a daily basis and serve as our primary reference for analyzing our blood glucose data. With that said, it’s easy to assume your readings are accurate. But that also means blood glucose meter accuracy is critical.

Blood glucose meter accuracy is important for several reasons: 

• Improved reliability in your data and trust in your current diabetes management plan.
• Helps you understand and/or anticipate potential lab results when going for your HbA1c checkup.
• Lets you know what impacts your blood sugar:
  • Did that glass of wine last night have a significant impact?
  • Did you experience a spike or drop in blood sugar after that amazing Zumba class?
  • Is there a connection between your stress and blood sugar?
• Accurate meters can detect episodes of hypo- or hyperglycemia.
• Can help with decision-making surrounding medication dosages.

Although you should follow the instructions provided with your meter, this guide will help you understand what impacts its validity and offer tips to ensure you get the most accurate result possible. An array of things can impact your readings, from the temperature to the testing location, as well as:

Blood glucose meter calibration, quality, and coding

To trust the data your meter is providing, ensure you’re using a quality meter. We discuss this more below, but manufacturers must meet certain standards to be considered accurate. If you’re unsure about the quality of the meter, check for the latest updates and versions from the maker.
When you first set up your meter, follow the directions included with it. The calibration process can vary depending on the manufacturer and meter. Finally, your meter will need to match a calibration code with the number on the test strip vial. Some meters are the exception to this. For example, with an Accu-Chek meter, there’s no need to code it, so you have fewer steps in glucose testing.

Test strip quality and compatibility

This is a major one. Using an incompatible test strip can cause inaccurate or error readings. Different manufacturers have their own processes for developing their test strips. Test strips also come with expiration dates – don’t use strips beyond the expiration date. Lastly, beware of using test strips that are unauthorized for sale or that were previously owned.

Standards and quality control

The Food and Drug Administration (FDA) sets standards for manufacturers producing blood glucose meters in the United States, while the International Organization for Standardization develops and publishes standards on a global scale. A position statement published in January 2019 compared the standards for blood glucose meter accuracy set by these two organizations.¹ Let’s take a look at the standards for the home use of these devices:

•  FDA: Readings are 95 percent accurate within 15 percent for all readings within the “usable” blood glucose range and 99 percent accurate within 20 percent for all readings within that usable range. The term “usable” in this context refers to the range of blood glucose values for which the meter has been proven to be accurate.
• ISO: Readings are 95 percent accurate within 15 percent of blood glucose equal to or above 5.5 mmol/L (100 mg/dL) and are 95 percent accurate within 0.83 mmol/L (15 mg/dL) for readings under 5.5 mmol/L (100 mg/dL).

Manufacturers also have their own quality control protocols and standards. For example, Accu-Chek’s strict manufacturing processes ensure their products meet uncompromising standards of quality.

• The company’s quality control process tests over 60,000 test strips for consistent accuracy.²
• For every lot of their test strips, which contain millions of strips, at least 1 out of every 128 vials is tested for consistency of performance. Vials are then tested a second time with blood at various glucose levels to reflect a real-world environment.
• Investigations and additional testing are conducted if a test strip sample displays a reading outside of specific ranges.

Another example is Accu-Chek’s advanced 10/10 accuracy, which is found in the Accu-Chek Instant system.³  95 percent of measured glucose results should fall within 0.55 mmol/L (10 mg/dL) of a lab reference value for blood glucose concentrations below 5.5 mmol/L (100 mg/dL) and 10 percent for blood glucose concentrations equal to or above 5.5 mmol/L (100 mg/dL). 

Cleanliness of your hands and testing site

Dirt, food, grease, or any other kind of residue at or around your testing site can skew your readings. Wash your hands before testing your blood sugar, and clean the area around your finger. Make sure your testing site is dry so as not to dilute the blood before taking your reading.

Testing technique and site

Make sure you’re following the directions of your meter. Traditionally, fingertips are the primary place to test your blood sugar. Alternative testing sites, such as on the palm, upper arm, forearm, thigh, and calf, are used, typically in clinical settings, instead of fingers due to the many nerve endings on fingers, including the pain from testing and the resulting calloused fingers. However, it isn’t advisable to use an alternative site unless you have a device specifically designed for it. However, using an alternate site may not always produce accurate results, especially if your blood sugar is rising or falling fast. Research shows that glucose readings differ depending on if you get your blood sample from the capillaries in your fingers or another part of your body.⁴

Another note about the technique: ensure you have sufficient blood in your test strip. Having too little blood will cause an error or a false reading. You can adjust the settings on your lancet to make sure you’re drawing enough blood. Finally, ensure that you fully insert the test strip into your meter.

Temperature/Environment

Avoid having your testing supplies in extreme heat or cold conditions. If you’re the type to leave your supplies in your car, avoid doing so if they’ll be left in extreme temperatures. High altitude can also affect your meter’s readings. Be sure to store your meter according to the manufacturer’s instructions.

Hematocrit

Your hematocrit represents the number of red blood cells in your blood. If you suffer from anemia or dehydration, your results may not be as accurate as those who have a normal blood cell count.⁵ Check with your provider to ensure you get accurate readings.

Medication

Drugs such as acetaminophen, dopamine, ascorbic acid (vitamin C), and mannitol can significantly impact the accuracy of certain glucose meters^.6 Acetaminophen and ascorbic acid can result in readings that show false lower readings. People with diabetes who are on dialysis, specifically peritoneal dialysis to treat kidney failure, are at risk for false higher readings due to a component that turns into maltose. As a result, the meter can confuse maltose for glucose.

Sources:

1. American Diabetes Association; 7. Diabetes Technology: Standards of Medical Care in Diabetes-2019. Diabetes Care. 2019; 42(S1): S71–S80.
2. Data on file. Based on average weekly strip production of approximately 80M, and includes a combination of testing test strips for accuracy and precision standards.
3. Breitenbeck N, Brown A. Accuracy Assessment of a Blood Glucose Monitoring System for Self-Testing with Three Test Strip Lots Following ISO 15197:2013/EN ISO 15197:2015. J Diabetes Sci Technol. 2015;11(4):854 855.
4. Tonyushkina K, Nichols JH. Glucose meters: a review of technical challenges to obtaining accurate results. J Diabetes Sci Technol. 2009;3(4):971-80.
5. Blood Glucose Monitoring Devices [Internet]. U.S. Food and Drug Administration. 2024 Nov 14 [cited 2025 July 10]. Available from: https://www.fda.gov/medical-devices/in-vitro-diagnostics/blood-glucose-monitoring-devices
6. Rice MJ, Coursin DB. Measuring glucose with point-of-care meters: Be careful! [Internet]. Anesthesia Patient Safety Foundation. 2021 Oct 1 [cited 2025 Jul 10].  Available from: https://www.apsf.org/article/measuring-glucose-with-point-of-care-meters-be-careful/