How to Test Your Blood Glucose (BG) Accurately Every Time

17 Sep 2025 By David A. Galbreath, M.D.

How to Test Your Blood Glucose (BG) Accurately Every Time

Accurate blood glucose (BG) testing is crucial for managing diabetes and maintaining overall health. Whether you're newly diagnosed or have been managing diabetes for years, knowing how to test your blood glucose correctly ensures you get reliable readings, allowing you to make informed decisions about your diet, medication, and physical activity. This comprehensive guide will walk you through the steps necessary for accurate blood glucose testing every time.

Why Accurate Blood Glucose Testing Matters

Accurate BG testing is essential for several reasons:

Effective Diabetes Management: It helps you understand how different factors affect your blood sugar levels.
Personalized Treatment Plans: Provides data for healthcare providers to tailor your diabetes management plan.
Prevention of Complications: Helps you avoid both hyperglycemia (high blood sugar) and hypoglycemia (low blood sugar), reducing the risk of long-term health issues.
Improved Quality of Life: Empowers you to take control of your health and make informed decisions daily.

Preparing for Accurate Blood Glucose Testing

Before you start, ensure you have everything you need and prepare your testing environment properly. Proper preparation minimizes errors and ensures reliable results. How To Manage Blood Sugar And Insulin Resistance With 5 Simple Changes

1. Gather Your Supplies

Make sure you have all the necessary supplies within reach:

Blood Glucose Meter: Choose a meter that is accurate, easy to use, and meets your specific needs.
Test Strips: Use the test strips specifically designed for your meter model. Ensure they are not expired and are stored properly in their original container.
Lancet Device and Lancets: A lancing device helps you prick your finger with minimal pain. Use a new, sterile lancet each time to prevent infection and ensure a clean sample.
Alcohol Swabs: Clean the fingertip before pricking.
Cotton Balls or Clean Gauze: To stop the bleeding after the test.
Sharps Container: Dispose of used lancets safely to prevent injury and infection.

2. Check the Expiration Dates

Expired test strips and control solutions can provide inaccurate readings.

| Item | Importance of Checking Expiration | |----------------|-------------------------------------------------------------------------------------------------------------------------| | Test Strips | Expired strips may give falsely high or low readings, leading to incorrect insulin dosages or dietary adjustments. | | Control Solution | Helps verify that your meter and test strips are working correctly. Expired solution may provide unreliable verification.| |Lancets| Check the lancet package to ensure that they are still in a sterile condition, which is necessary for injection process. | What Is A Normal Blood Sugar Range And Why Does It Matter

3. Wash and Dry Your Hands

Thoroughly washing your hands is crucial for accurate results.

Use Warm Water: Wash your hands with warm, soapy water.
Scrub Thoroughly: Scrub for at least 20 seconds, ensuring you clean between your fingers and under your nails.
Rinse Well: Rinse your hands completely under running water.
Dry Completely: Use a clean towel to dry your hands. Make sure your hands are completely dry, as any remaining water can dilute the blood sample and affect the reading.

4. Calibrate Your Meter

Follow your meter’s instructions to calibrate it correctly, especially when you open a new batch of test strips.

5. Run a Control Test (If Needed)

If you suspect your meter or test strips aren’t working correctly, perform a control test.

Use Control Solution: Apply the control solution to a test strip as if it were a blood sample.
Compare Results: Compare the result on your meter with the range printed on the test strip vial. If the reading is within the specified range, your meter and strips are working correctly.

Step-by-Step Guide to Accurate Blood Glucose Testing

Follow these steps for consistent and accurate blood glucose readings:

1. Prepare the Lancing Device

Insert a New Lancet: Place a new, sterile lancet into the lancing device.
Adjust the Depth Setting: Adjust the depth setting on the lancing device according to your skin type. Start with a lower setting and increase if necessary to obtain an adequate blood drop.

2. Choose the Right Finger

Rotate Fingers: Use different fingers each time to avoid soreness.
Use the Sides of Your Fingertips: Prick the sides of your fingertips rather than the center. There are fewer nerve endings on the sides, making the process less painful.
Avoid Calloused or Scarred Areas: These areas may not produce an adequate blood sample.

3. Clean the Puncture Site

Use an Alcohol Swab: Wipe the selected fingertip with an alcohol swab.
Allow to Dry: Let the alcohol dry completely before pricking your finger. Residual alcohol can affect the blood glucose reading.

4. Prick Your Finger

Press the Lancing Device: Press the lancing device firmly against the side of your fingertip and press the release button to prick your finger.
Avoid Squeezing Excessively: Gently massage your finger towards the puncture site. Avoid squeezing too hard, as this can dilute the blood sample with tissue fluid and lead to inaccurate results.

5. Apply the Blood Sample

Apply Blood to Test Strip: Hold the test strip near the blood drop, and allow the strip to draw the blood in automatically.
Ensure Adequate Sample Size: Make sure the blood sample is adequate to fill the test strip window completely. Insufficient blood can cause an error message or an inaccurate reading.
Avoid Smearing the Blood: Do not smear the blood on the test strip, as this can also lead to inaccurate results.

6. Read and Record the Result

Wait for the Reading: Wait for the meter to display the blood glucose reading. This usually takes a few seconds.
Record the Result: Write down the reading in a logbook, diabetes management app, or electronic health record.
Note the Time and Context: Record the date, time, and any relevant information, such as meals, medications, or physical activity.

7. Properly Dispose of Used Supplies

Dispose of Lancets: Place used lancets in a sharps container immediately.
Follow Local Guidelines: Follow local guidelines for the proper disposal of sharps containers.

Troubleshooting Common Issues

Even with careful preparation, you might encounter some common issues. Here’s how to troubleshoot them:

1. Insufficient Blood Sample

Massage Your Finger: Gently massage your finger toward the puncture site to encourage blood flow.
Lower Your Hand: Hold your hand down below your heart level to increase blood flow to your fingertips.
Try a Deeper Lancet Setting: If necessary, increase the depth setting on your lancing device.
Ensure Hydration: Dehydration can reduce blood flow. Drink water before testing.

2. Error Messages on the Meter

Check the Test Strip: Ensure the test strip is properly inserted into the meter.
Replace the Test Strip: Try a new test strip, as the current one may be damaged or faulty.
Consult the Meter Manual: Refer to your meter’s user manual for specific error codes and troubleshooting steps.

3. Readings That Seem Inaccurate

Check the Expiration Date: Ensure your test strips and control solution are not expired.
Repeat the Test: Retest using a new test strip and a fresh blood sample.
Perform a Control Test: Run a control test to ensure your meter and test strips are working correctly.
Consider External Factors: Consider if factors like stress, illness, or recent meals might be affecting your blood glucose levels.
Contact Your Healthcare Provider: If you consistently get readings that don’t match how you feel, consult your healthcare provider.

Factors Affecting Blood Glucose Readings

Several factors can influence your blood glucose readings. Being aware of these can help you interpret your results more accurately.

| Factor | How It Affects BG | What to Do | |-----------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------| | Food Intake | Carbohydrates raise blood glucose levels. The type, amount, and timing of food intake significantly affect readings. | Monitor carbohydrate intake and adjust insulin or medication as prescribed by your healthcare provider. | | Physical Activity | Exercise can lower blood glucose during and after activity. Intense exercise can sometimes raise blood glucose in the short term due to stress hormones. | Adjust insulin or carbohydrate intake based on your exercise routine, as advised by your healthcare provider. | | Medication | Insulin and other diabetes medications directly impact blood glucose levels. Dosage adjustments affect readings. | Follow your prescribed medication schedule and dosage instructions carefully. | | Stress | Stress hormones can raise blood glucose levels. | Practice stress-reduction techniques, such as meditation, yoga, or deep breathing exercises. | | Illness | Illness and infections can cause blood glucose levels to rise due to the release of stress hormones. | Monitor blood glucose levels more frequently when ill and follow your sick-day management plan. | | Hydration | Dehydration can lead to higher blood glucose readings due to the concentration of glucose in the blood. | Stay adequately hydrated by drinking plenty of water throughout the day. | | Time of Day | Blood glucose levels naturally fluctuate throughout the day due to hormonal changes and metabolic processes. | Be aware of typical patterns in your blood glucose levels at different times of the day. | | Alcohol Consumption | Alcohol can initially lower blood glucose but may lead to hypoglycemia later, especially if consumed on an empty stomach. | Consume alcohol in moderation and with food. Monitor blood glucose levels carefully after drinking alcohol. | | Menstrual Cycle | Hormonal changes during the menstrual cycle can affect blood glucose levels in women with diabetes. | Track your menstrual cycle and be prepared to adjust insulin or medication as needed. | | Temperature Extremes | Exposure to extreme temperatures can affect meter accuracy. | Avoid testing in extreme temperatures. Store your meter and test strips at room temperature. | How To Read Your Blood Sugar Level Results Like A Pro

Advanced Tips for Consistent Accuracy

For those who want to optimize their blood glucose testing even further, here are some advanced tips:

1. Maintain a Detailed Testing Log

Keep a comprehensive record of your blood glucose readings, including:

Date and Time: Accurate timestamps for each reading.
Meals and Snacks: Record what you ate, including carbohydrate content.
Medications: Note the type and dosage of medications taken.
Physical Activity: Describe the type and duration of exercise.
Stress Levels: Note any significant stress or emotional events.
Illness: Record any symptoms of illness.
Additional Notes: Any other relevant information, such as sleep quality or menstrual cycle phase.

2. Use Continuous Glucose Monitoring (CGM)

Consider using a Continuous Glucose Monitor (CGM) for real-time glucose tracking.

Benefits of CGM:
- Real-Time Data: Provides continuous glucose readings, eliminating the need for frequent fingersticks.
- Trend Information: Shows trends in glucose levels, helping you anticipate highs and lows.
- Alerts and Alarms: Alerts you to potentially dangerous high or low glucose levels.
Consult Your Healthcare Provider: Discuss whether a CGM is right for you with your healthcare provider.

3. Regularly Evaluate and Update Your Testing Technique

Assess Your Technique: Periodically review your testing technique to identify any areas for improvement.
Seek Professional Guidance: Consult a certified diabetes educator (CDE) for personalized advice and support.
Stay Informed: Stay up-to-date on the latest recommendations and advancements in blood glucose monitoring technology.

Conclusion

Accurate blood glucose testing is an essential component of effective diabetes management. By following the steps outlined in this guide, you can ensure that you obtain reliable readings, make informed decisions about your health, and improve your overall quality of life. Remember to prepare thoroughly, use the correct technique, troubleshoot common issues, and stay informed about factors that can affect your blood glucose levels. Regular monitoring and careful attention to detail will empower you to take control of your health and live well with diabetes. Always consult with your healthcare provider for personalized advice and guidance.