Diabetes Test: How to Understand Blood Sugar Levels and Diagnosis

Medically Reviewed by:Scientific Advisory Board

Understanding and managing blood sugar levels is a critical aspect of living with diabetes. With a plethora of tests and devices available, it can be overwhelming to navigate the world of diabetes management.

In this comprehensive guide, we’ll explore various diabetes test options, interpret blood sugar levels, and provide essential tips for preparing and monitoring blood sugar at home. Let’s embark on this journey towards better diabetes management together.

Important Information about Diabetes Tests

  • Understanding Diabetes Tests allows for the recognition of various tests which can aid in diagnosing and managing diabetes.

  • Normal blood sugar levels may vary depending on the individual, while high or low levels warrant Investigation with a healthcare provider.

  • At-home monitoring is an important tool for diabetes management. Consult your doctor regularly to ensure optimal health outcomes.

Understanding Diabetes Tests

diabetes test

Diabetes tests play a vital role in diagnosing and managing diabetes by detecting abnormal blood sugar levels. But did you know that there are different types of diabetes tests? This section will delve into the following tests, each with its own unique purpose and procedure in helping you stay on top of your diabetes management:

  1. A1C test

  2. Fasting blood sugar test

  3. Random blood sugar test

  4. Glucose tolerance test

The A1C test is a blood test. It measures your average blood sugar level over the past few months.

A1C Test

The A1C test, also known as the hemoglobin A1C, HbA1C, glycated hemoglobin, or glycosylated hemoglobin test, is a laboratory test that provides an estimate of a person’s average blood sugar levels over the last three months. This test is crucial in determining how well you’re managing your diabetes and helps your healthcare provider make necessary adjustments to your treatment plan.

A typical A1C test result is below 5.7%. By measuring your average blood sugar levels over an extended period, the A1C test can help identify trends and fluctuations in your blood sugar control. This valuable information can assist you and your healthcare provider in making informed decisions about your diabetes management.

Fasting Blood Sugar Test

The fasting blood sugar test, also known as the fasting blood glucose test, is another essential diabetes test, requiring you to fast for 8-10 hours before the test. The normal range for fasting blood sugar levels is 70-100 mg/dL, prediabetes is indicated by a range of 100-126 mg/dL, and diabetes is indicated by a fasting blood sugar level of 126 mg/dL and above.

It’s important to note that other medical conditions may be associated with elevated or decreased blood glucose levels. Therefore, fasting blood sugar tests are crucial in identifying potential health issues and ensuring timely intervention.

Random Blood Sugar Test

Random blood sugar test is used to determine the level of sugar in the blood at the time of testing. It does not require fasting beforehand. This test can only detect diabetes, not prediabetes, and is typically utilized to diagnose diabetes when symptoms are present but fasting for 8 hours isn’t feasible.

A random blood sugar test can be conducted using a home kit or at a diagnostic center. This convenient test allows for quick results and can provide valuable insights into your blood sugar levels throughout the day.

Glucose Tolerance Test

The glucose tolerance test is a diagnostic procedure assessing the body’s response to sugar or glucose. This test serves as a screening tool for type 2 diabetes and gestational diabetes. The American Diabetes Association recommends that adults aged 45 years and older receive type 2 diabetes screenings every three years, with earlier and more frequent screenings for those considered overweight or obese.

Pregnant women are advised to be tested for gestational diabetes between 24 and 28 weeks of pregnancy using the glucose challenge test, which involves consuming a sweet liquid containing glucose and measuring blood glucose levels one hour after consumption. This test helps ensure the wellbeing of both mother and baby during pregnancy.

Blood Sugar Levels: What They Mean

Interpreting your blood sugar levels is crucial in managing diabetes and maintaining overall health. In this section, we’ll explore normal, high, and low blood sugar levels, as well as their implications on your health and wellbeing.

By understanding these levels, you’ll be better equipped to make informed decisions about your diabetes management and overall health.

Normal Blood Sugar Levels

Blood glucose levels are measured after fasting. Normal range for this measure is 70-100 mg/dL (3.9 to 5.6 mmol/L). However, it’s essential to understand that normal blood sugar levels may vary depending on the individual, and there are generally accepted ranges considered to be within the normal range.

Individuals who are thin and younger often have a lower normal fasting blood sugar level. For instance, this can be as low as 70 mg/dL (3,9 mmol/L). A normal glucose level for individuals without diabetes is between 50 and 70 mg/dL (2.8 to 3.9 mmol/L). These figures are widely seen as a healthy range.

It’s essential to discuss your blood sugar levels with your healthcare provider to determine what’s considered normal for you.

High Blood Sugar Levels

High blood sugar levels can indicate prediabetes or diabetes. A fasting blood glucose level of 126 mg/dl (7.0 mmol/L) or higher indicates diabetes. This is indicated by the results of more than one testing occasion. Blood sugar levels of more than 200 mg/dL (11.1 mmol/L) are also indicative of elevated blood sugar levels and may point towards prediabetes or diabetes.

Various factors, such as diet, lifestyle, and genetics, may contribute to elevated blood sugar levels. If you have prediabetes, it’s important to make lifestyle changes to reduce the risk of developing type 2 diabetes, which can be as high as 50%. Consult your healthcare provider if you experience concerning symptoms or abnormal blood sugar levels.

Low Blood Sugar Levels

Low blood sugar, or hypoglycemia, occurs when blood sugar levels fall below the target range. A blood sugar result of 70 mg/dL or less is typically regarded as low. Symptoms of low blood sugar include:

  • Dizziness

  • Confusion

  • Sweating

  • Hunger

  • Shakiness

  • Fatigue

The most effective way to treat low blood sugar is to consume carbohydrates that can be quickly absorbed by the body, such as fruit juice or glucose tablets. It’s crucial to monitor your blood sugar levels regularly and discuss any concerns with your healthcare provider.

Preparing for a Blood Sugar Test

Proper preparation is key to ensuring accurate results from your blood sugar test. In this section, we’ll discuss fasting requirements and other considerations to help you get the most accurate results from your blood sugar test.

By following these guidelines, you’ll be better prepared for your test and more confident in managing your diabetes.

Fasting Requirements

Fasting is the act of abstaining from food and drink for a predetermined period of time. For a fasting blood sugar test or glucose tolerance test, it’s recommended that you fast for 8-10 hours prior to the test. It’s important to adhere to fasting requirements, as failure to do so can result in inaccurate test results and incorrect diagnosis.

During the fasting period, you should only drink water and avoid consuming any other beverages, such as coffee or tea. If you’re unsure about your fasting requirements, consult your healthcare provider for advice on how to best prepare for your blood sugar test.

Pre-test Considerations

In addition to fasting, there are other pre-test considerations to keep in mind when preparing for a blood sugar test. Medication adjustments may be necessary before taking the test, including insulin or oral diabetes medications. Be sure to consult your healthcare provider for guidance on medication adjustments.

Also, avoid consuming food and beverages that may influence the test results, such as alcohol, and refrain from engaging in strenuous exercise prior to the test. By taking these pre-test considerations into account, you’ll be better prepared for your blood sugar test and more likely to receive accurate results.

Blood Sugar Test Procedure and Risks

Now that we’ve covered preparation for a blood sugar test, let’s delve into the test procedure itself, what to expect during the test, and potential risks associated with the test. Understanding these aspects will help you feel more comfortable and confident during your blood sugar test, ensuring a smoother experience overall.

The test procedure itself is relatively simple and straightforward. A healthcare professional will draw a small sample.

Capillary vs. Venous Blood Glucose Tests

When it comes to blood sugar tests, there are two main types: capillary and venous blood glucose tests. A capillary blood glucose test, also known as a fingerstick test, involves pricking your finger to obtain a small blood sample. Healthcare professionals, such as nurses, are qualified to administer capillary blood glucose tests.

On the other hand, a vein blood glucose test requires obtaining a blood sample from a vein. Vein blood tests are generally more accurate for measuring blood glucose levels than a fingerstick with a blood glucose meter or a continuous glucose monitor. It’s important to use reliable methods when monitoring one’s blood sugar levels.

It’s crucial to discuss with your healthcare provider which type of test is most suitable for your needs.

Test Sensations and Recovery

During a blood sugar test, you may experience moderate pain upon needle insertion for drawing blood, while others may experience a prick or stinging sensation. Subsequently, some may experience throbbing or slight bruising at the site of the blood draw. However, these sensations are typically short-lived and should not cause significant discomfort.

In terms of recovery, most people can resume their normal activities immediately following a blood sugar test. If you experience any prolonged discomfort or symptoms, it’s essential to consult your healthcare provider for guidance and assistance.

Potential Risks

While blood sugar tests are generally safe, there are some potential risks to be aware of. These may include:

  • Slight tenderness or bruising at the site of the blood draw

  • Soreness, swelling, and bruising at the puncture site

  • The potential for exposure to bloodborne viruses if contaminated equipment is utilized

However, these risk factors are infrequent and should not deter you from taking the test.

If you experience any unusual or severe symptoms following a blood sugar test, it’s crucial to consult your healthcare provider. They can help address any concerns and ensure you receive the best care possible.

Monitoring Blood Sugar Levels at HomeAt-home blood sugar monitoring can be an empowering tool for those living with diabetes. In this section, we’ll explore the use of glucose meters and continuous glucose monitoring systems (CGMs) for effective blood sugar management at home. By learning about these devices and their proper use, you’ll be well-equipped to take control of your diabetes management.

It’s important to understand the basics of how glucose meters and CGMs work.

Glucose Meters

Glucose meters, or blood glucose monitors, are devices used to measure and monitor blood sugar levels. They’re often employed by individuals with diabetes to regulate their condition more effectively. To use a glucose meter and test strips, you must:

  1. Insert a test strip into the meter

  2. Prick your finger with a lancet

  3. Place a drop of blood on the test strip

  4. The meter will then measure your blood sugar level and display the result.

Glucose meters offer a rapid and convenient method to check blood sugar levels at home or while traveling, making them an invaluable tool for diabetes management. By regularly monitoring your blood sugar levels with a glucose meter, you can better understand how various factors, such as diet and exercise, impact your blood sugar levels and make necessary adjustments to your diabetes management plan.

Continuous Glucose Monitoring Systems

Continuous glucose monitoring (CGM) devices are another powerful tool for effective blood sugar management. These devices, worn on the body, provide continuous measurement of blood sugar levels and are connected to an app on a smartphone or other device, which will alert you when your blood sugar levels are outside of the desired range.

CGMs offer several benefits, such as reducing the frequency of fingersticks required to monitor blood sugar levels and providing valuable insights into trends in blood sugar levels. By utilizing a CGM, you can gain a more comprehensive understanding of your blood sugar levels and make informed decisions about your diabetes management.

When to Consult Your Doctor

Knowing when to consult your healthcare provider regarding your blood sugar levels or concerning symptoms is crucial in managing diabetes effectively. In this section, we’ll discuss when to seek professional advice and the importance of regular check-ups for optimal diabetes management.

It is important to consult your healthcare provider if you experience any symptoms that could be related to diabetes.


In conclusion, understanding and managing blood sugar levels are essential for living well with diabetes. By familiarizing yourself with various diabetes tests, interpreting blood sugar levels, and utilizing at-home monitoring devices, you can take control of your diabetes management with confidence. Don’t hesitate to consult your healthcare provider with any concerns or questions, as they are your greatest ally in your journey towards better diabetes management. Stay informed, stay proactive, and stay healthy!

Frequently Asked Questions

How do you get tested for diabetes?

To get tested for diabetes, a simple blood test is usually the first step. This test will measure your current blood glucose level and if it reveals a level of above 125 mg/dl, your doctor will ask you to repeat the test on a different day.

Additional blood tests may also be taken, such as an A1C test, Fasting Blood Sugar Test, or Glucose Tolerance Test, to confirm the diagnosis. Only through blood tests can you find out whether you or a loved one has diabetes, which can be arranged through your GP.

What are 10 warning signs of diabetes?

Be aware of warning signs of diabetes, such as excessive thirst, frequent urination, unexplained weight loss, feeling tired and weak, mood changes, blurry vision, ketones in the urine, slow-healing sores, and increased hunger.

Don’t ignore any of these indicators of possible diabetes.

What is the normal sugar level?

A healthy fasting blood sugar level is between 70 to 100 mg/dL (3.9 to 5.6 mmol/L). Prediabetes is indicated if the level is between 100 to 125 mg/dL (5.6 to 6.9 mmol/L).

Diabetes is indicated if the level is 126 mg/dL (7 mmol/L) or higher.

How do I know exactly I have diabetes?

To definitively know if you have diabetes, it is important to visit your doctor for regular check-ups and blood tests. If you have risk factors such as a family history of diabetes, these tests are even more necessary.

It is important to be aware of the signs and symptoms of diabetes, such as increased thirst, frequent urination, and fatigue. If you experience any of these symptoms, it is important to visit your doctor.

What is the difference between the A1C test and the fasting blood sugar test?

The A1C test provides an average of blood sugar levels over the last three months, whereas the fasting blood sugar test measures glucose levels after a fast of 8-10 hours.

Both tests are vital for diabetes diagnosis and management.

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Dr. Capozzi is a board-certified foot surgeon through the American Board of Foot and Ankle Surgery. He is a Diplomate of the American Academy of Wound Management and Fellow of the American College of Foot and Ankle Surgeons. He completed a three-year residency program in Foot and Ankle Reconstructive Surgery at St. Francis Hospital & Medical Center in Hartford, CT in 2010. Dr. Capozzi is a board-certified Wound Specialist® granted by the American Academy of Wound Management. He is also board-certified in Foot Surgery through the American Board of Foot and Ankle Surgery.