Mistakes to Avoid When Testing Your Fasting Blood Sugar at Home

Testing your fasting blood sugar at home is a crucial part of managing diabetes or prediabetes. It gives you and your healthcare provider valuable insights into how well your body is processing glucose after a period of not eating. However, inaccurate readings due to common mistakes can lead to confusion and potentially incorrect treatment decisions. This article highlights the common errors people make when testing their fasting blood sugar at home and provides guidance on how to avoid them.

Understanding Fasting Blood Sugar

Before diving into the mistakes, it's important to understand what fasting blood sugar actually measures. It reflects your blood glucose level after you’ve abstained from food and caloric beverages for at least eight hours. This measurement helps determine how well your body regulates blood sugar on its own without the influence of recent food intake. For most people, testing is recommended first thing in the morning before eating or drinking anything (except water).

Common Mistakes and How to Avoid Them

1. Not Fasting for Long Enough

• The Mistake: Eating or drinking caloric beverages too close to the testing time. Anything with calories will affect your blood sugar. Even a small snack or a sugary drink can skew the results.
• The Solution: Aim for a strict fast of at least 8 hours. Typically, an overnight fast works best. Finish eating dinner early, and don't consume anything besides water before your test in the morning. Document the time you last ate, so you can determine if you fasted long enough. If you have night time hypoglycemia, talk to your doctor about testing options that account for these exceptions.

2. Improper Hand Washing

• The Mistake: Having dirty or contaminated hands when testing. Even small amounts of food residue, lotion, or other substances on your fingertips can contaminate the blood sample and lead to falsely elevated readings.
• The Solution: Wash your hands thoroughly with soap and warm water. Dry them completely with a clean towel. Avoid using alcohol-based hand sanitizers right before testing, as they can sometimes contain ingredients that affect blood sugar levels.

3. Using Expired or Damaged Test Strips

• The Mistake: Test strips have an expiration date. Using expired strips or strips that have been improperly stored (exposed to heat, humidity, or air) can lead to inaccurate results.
• The Solution: Always check the expiration date on your test strip vial before using them. Store the strips in a cool, dry place as indicated on the packaging. Keep the vial tightly closed to protect the strips from moisture and air. Discard the vial if the strips appear discolored or damaged. Never use test strips past their expiration date, even if they appear to be in good condition.

4. Incorrect Meter Calibration and Coding

• The Mistake: Some blood glucose meters require coding or calibration each time a new batch of test strips is used. Failing to code the meter correctly can result in readings that are significantly off.
• The Solution: Carefully read the instructions that came with your blood glucose meter. If your meter requires coding, make sure to enter the correct code that matches the number printed on the test strip vial. Some newer meters automatically calibrate, which simplifies the process. If you have any doubts, consult your meter's user manual or contact the manufacturer's customer service for assistance. Perform a control solution test according to the manufacturer's instructions periodically, especially if you suspect your meter might be malfunctioning.

5. Not Using Enough Blood

• The Mistake: Insufficient blood sample size. Applying too little blood to the test strip can cause the meter to display an error message or produce an inaccurate reading.
• The Solution: Ensure you are using enough blood to completely fill the test strip’s sample area. Some meters require a very small drop, while others need more. If the meter gives you an error message indicating insufficient blood, do not add more blood to the same strip. Discard the used strip and repeat the test with a new one, making sure to obtain an adequate blood sample. Try gently massaging or squeezing your finger (but avoid excessive squeezing) to encourage blood flow. Consider warming your hands before pricking to improve circulation.

6. Not Pricking Deep Enough

• The Mistake: Pricking the finger too lightly. If the lancing device is not set to a sufficient depth, you may not obtain a large enough blood sample.
• The Solution: Adjust the depth setting on your lancing device until you consistently get a sufficient blood sample without excessive squeezing. Most lancing devices have adjustable settings to accommodate different skin thicknesses. Experiment to find the setting that works best for you. Consider pricking the side of your fingertip, as this area tends to be less sensitive. Rotate fingers used for testing to avoid soreness.

7. Using the Wrong Finger

• The Mistake: Consistently using the same finger to test.
• The Solution: Rotate which finger you use to test. Testing too frequently on the same finger can cause soreness, bruising, or even calluses. Alternate between fingers and sides of fingers. The middle and ring fingers are often recommended, as they tend to have better blood flow.

8. Ignoring Control Solutions

• The Mistake: Never using control solutions to verify the accuracy of the meter and test strips.
• The Solution: Use control solutions regularly, especially when you open a new vial of test strips, suspect that your meter might be malfunctioning, or if your blood sugar readings seem unusually high or low. Follow the instructions provided with your meter and control solution to perform the test properly. Consult your meter's user manual for guidance on interpreting the control solution results. If the results fall outside the acceptable range, consult your doctor or pharmacist.

9. Not Recording Results Accurately

• The Mistake: Failing to keep a log of your fasting blood sugar results or recording them inaccurately.
• The Solution: Maintain a detailed record of your fasting blood sugar readings, including the date, time, and results of each test. Use a notebook, spreadsheet, or a dedicated blood sugar tracking app on your smartphone. Be sure to note any factors that might affect your blood sugar levels, such as medication changes, illness, stress, or unusual activity. Accurate record-keeping allows you and your healthcare provider to identify trends, patterns, and potential problems.

10. Disregarding Medical Advice

• The Mistake: Adjusting medication or treatment without consulting your healthcare provider.
• The Solution: Always consult with your doctor or diabetes educator before making any changes to your medication, diet, or exercise regimen based on your fasting blood sugar results. Self-treating can be dangerous and may lead to complications. Your healthcare provider can interpret your blood sugar readings in the context of your overall health and help you make informed decisions about your diabetes management plan.

What to Do If You Get an Unexpected Result

If you get a fasting blood sugar reading that is significantly higher or lower than usual, don't panic. Repeat the test using a fresh test strip and a clean finger. If the second reading is also unusual, contact your healthcare provider for guidance. Be prepared to provide them with information about your recent activity, diet, and any medications you are taking. They may recommend additional testing or adjustments to your treatment plan.

Fasting Blood Sugar Target Ranges (HTML Table)

Note: These ranges are general guidelines. Your target range may vary depending on your individual health conditions and treatment plan. Always consult with your healthcare provider for personalized recommendations.

Conclusion

Regular fasting blood sugar monitoring at home is a valuable tool for managing diabetes or prediabetes. By avoiding the common mistakes outlined above, you can ensure that you are getting accurate and reliable readings. Remember to follow the instructions provided with your blood glucose meter, store your test strips properly, and consult with your healthcare provider if you have any questions or concerns. Taking these steps will help you effectively manage your blood sugar levels and improve your overall health.