How to Read a Blood Sugar Test and Understand Your Range

18 Sep 2025 By Jeff P. Nadwodny, D.O.

How to Read a Blood Sugar Test and Understand Your Range

Understanding your blood sugar levels is crucial for managing your overall health, particularly if you have diabetes or are at risk of developing it. A blood sugar test, also known as a glucose test, measures the amount of glucose in your blood. This article will guide you through how to read the results, understand what the numbers mean, and what steps you can take based on your blood sugar range. By the end, you'll be well-equipped to interpret your results and make informed decisions about your health.

Why Monitoring Blood Sugar is Important

Regular monitoring of blood sugar levels is essential for several reasons:

Diabetes Management: It allows individuals with diabetes to adjust medication, diet, and exercise to keep their blood sugar within the target range.
Early Detection: Monitoring can help identify prediabetes, a condition where blood sugar levels are higher than normal but not high enough to be diagnosed as diabetes. Early detection allows for lifestyle changes to prevent or delay the onset of type 2 diabetes.
Preventing Complications: Keeping blood sugar levels within a healthy range can reduce the risk of long-term complications of diabetes, such as heart disease, kidney disease, nerve damage, and vision problems.
Informed Decision-Making: Knowing your blood sugar levels empowers you to make informed decisions about your diet, physical activity, and medication.

Types of Blood Sugar Tests

Before diving into how to read your results, it's important to understand the different types of blood sugar tests available:

Fasting Blood Sugar (FBS): This test is taken after an overnight fast (usually at least 8 hours). It’s a common way to screen for diabetes.
Random Blood Sugar (RBS): This test is taken at any time, regardless of when you last ate. It's often used when symptoms of diabetes are present.
Oral Glucose Tolerance Test (OGTT): This test involves fasting overnight, then drinking a sugary liquid. Blood sugar levels are tested periodically for the next two hours. It's often used to diagnose gestational diabetes.
A1C Test (Glycated Hemoglobin): This test provides an average of your blood sugar levels over the past 2-3 months. It doesn't require fasting and gives a broader picture of blood sugar control.
Continuous Glucose Monitoring (CGM): A device is inserted under the skin to track glucose levels continuously throughout the day and night. It provides real-time data and trends.

Understanding which test you’ve taken is the first step in interpreting your results accurately.

How to Read Your Blood Sugar Test Results

Once you have your blood sugar test results, it’s crucial to understand what the numbers mean. The unit of measurement commonly used is milligrams per deciliter (mg/dL). Here’s a breakdown of how to interpret results from the common types of blood sugar tests:

1. Fasting Blood Sugar (FBS) Test

The fasting blood sugar test is taken after an overnight fast. Here's how to interpret the results:

Example:

If your FBS result is 90 mg/dL, it falls within the normal range.
If your FBS result is 115 mg/dL, it indicates prediabetes.
If your FBS result is 130 mg/dL, it suggests diabetes, and your doctor will likely order a repeat test to confirm.

2. Random Blood Sugar (RBS) Test

This test is taken at any time of the day without regard to meals. It is most useful for detecting high blood sugar levels in individuals experiencing symptoms of diabetes. Unlock The Link Between Blood Sugar And Weight Loss A Complete Guide

Important Considerations: Since RBS can be affected by when you last ate, it is less reliable as a standalone diagnostic test. Abnormal results typically warrant a follow-up with a fasting blood sugar test or A1C test for a more accurate assessment.

Example:

If your RBS result is 150 mg/dL and you have no symptoms, it's likely normal.
If your RBS result is 220 mg/dL, and you're experiencing increased thirst and frequent urination, it suggests diabetes. Consult your doctor for further evaluation.

3. Oral Glucose Tolerance Test (OGTT)

The OGTT is a series of blood sugar tests taken over a 2-hour period after drinking a sugary solution. It’s commonly used to diagnose gestational diabetes during pregnancy.

For Gestational Diabetes (Diagnostic criteria may vary slightly):

Fasting: 95 mg/dL or higher
1-hour: 180 mg/dL or higher
2-hour: 153 mg/dL or higher

If two or more values meet or exceed these levels, gestational diabetes is diagnosed.

Example:

If your 2-hour OGTT result is 130 mg/dL, it falls within the normal range.
If your 2-hour OGTT result is 160 mg/dL, it indicates impaired glucose tolerance.
If your 2-hour OGTT result is 210 mg/dL, it suggests diabetes.

4. A1C Test

The A1C test measures your average blood sugar level over the past 2-3 months. It’s a key test for diabetes management. Unlike other blood sugar tests, the A1C test does not require fasting. The result is given as a percentage.

Estimated Average Glucose (eAG): A1C can be converted to an estimated average glucose level (eAG), which gives you an idea of what your average daily blood sugar is in mg/dL. Here's a simple conversion:

| A1C (%) | eAG (mg/dL) | | :------ | :---------- | | 6 | 126 | | 7 | 154 | | 8 | 183 | | 9 | 212 | | 10 | 240 |

Example:

If your A1C result is 5.2%, it falls within the normal range, indicating good long-term blood sugar control. The eAG is approximately 103 mg/dL.
If your A1C result is 6.0%, it indicates prediabetes, suggesting a need for lifestyle changes to prevent progression to diabetes. The eAG is approximately 126 mg/dL.
If your A1C result is 7.0%, it suggests diabetes and a need for closer management of blood sugar levels. The eAG is approximately 154 mg/dL.

5. Continuous Glucose Monitoring (CGM)

CGM devices provide real-time blood sugar readings throughout the day and night, enabling more precise diabetes management. Readings are displayed on a receiver or smartphone. These devices help monitor fluctuations and patterns, facilitating timely adjustments to medication, diet, and physical activity. Top 5 Factors Affecting Blood Sugar That May Surprise You

Target Range: Generally, the target range for CGM readings is between 70-180 mg/dL.
Time in Range (TIR): A crucial metric derived from CGM data. It indicates the percentage of time glucose levels are within the target range. A TIR of 70% or more is often recommended for people with diabetes to reduce the risk of complications.

Example:

If your CGM consistently shows readings below 70 mg/dL (hypoglycemia), you might need to adjust your insulin dose or meal plan.
If your CGM frequently displays readings above 180 mg/dL (hyperglycemia), it may indicate a need for changes in medication, diet, or exercise routine.

Factors Influencing Blood Sugar Levels

It’s important to recognize that several factors can influence blood sugar levels, leading to fluctuations throughout the day. These factors include:

Food and Drinks: Carbohydrates raise blood sugar levels more than proteins or fats. The type, quantity, and timing of meals all play a role.
Physical Activity: Exercise can lower blood sugar levels. The duration and intensity of physical activity matter.
Medications: Certain medications, such as insulin and oral diabetes drugs, directly impact blood sugar levels.
Stress: Stress hormones can raise blood sugar levels.
Illness: Illness can cause blood sugar levels to rise.
Hormonal Changes: Hormonal fluctuations, such as those experienced during menstruation or pregnancy, can affect blood sugar levels.
Dehydration: Being dehydrated can lead to higher blood sugar concentrations.
Alcohol: Alcohol can initially lower blood sugar, but can later cause it to rise, especially if consumed in large quantities.
Sleep: Inadequate or disrupted sleep can affect insulin sensitivity and glucose metabolism.

Understanding these factors can help you anticipate and manage blood sugar fluctuations more effectively.

Understanding Your Range: What to Do Based on Your Blood Sugar Levels

Once you know your blood sugar levels, it's important to understand what actions you can take. Here’s a guide to managing your blood sugar based on different ranges:

1. Low Blood Sugar (Hypoglycemia)

Definition: Blood sugar level below 70 mg/dL.

Symptoms: Shakiness, sweating, dizziness, hunger, confusion, irritability, blurred vision, headache.

Actions:

Treat Immediately: Consume 15-20 grams of fast-acting carbohydrates (e.g., glucose tablets, juice, regular soda).
Wait and Recheck: Wait 15 minutes and recheck your blood sugar.
Repeat if Necessary: If blood sugar is still below 70 mg/dL, repeat the treatment.
Eat a Snack: Once your blood sugar is back in the normal range, eat a snack containing both carbohydrates and protein to prevent another drop (e.g., crackers with peanut butter, cheese and fruit).
Consult Your Doctor: Discuss frequent or severe hypoglycemia with your doctor to adjust your diabetes management plan.
Wear a Medical Alert: Consider wearing a medical alert bracelet or necklace to inform others about your diabetes in case of emergency.

2. Normal Blood Sugar

Definition: Fasting blood sugar less than 100 mg/dL, A1C less than 5.7%.

Actions:

Maintain Healthy Habits: Continue with a balanced diet, regular physical activity, and sufficient sleep.
Regular Monitoring: If you have risk factors for diabetes, such as a family history or being overweight, continue to monitor your blood sugar levels as recommended by your doctor.
Stay Hydrated: Drink plenty of water throughout the day.
Manage Stress: Practice stress-reduction techniques such as meditation or yoga.

3. Prediabetes

Definition: Fasting blood sugar between 100-125 mg/dL, A1C between 5.7-6.4%.

Actions:

Lifestyle Changes: Focus on weight loss, regular physical activity (at least 150 minutes per week), and a balanced diet low in processed foods and sugary drinks.
Diet Modification: Reduce intake of refined carbohydrates, sugary beverages, and saturated fats. Increase intake of fiber-rich foods like fruits, vegetables, and whole grains.
Physical Activity: Engage in regular exercise to improve insulin sensitivity. This can include brisk walking, jogging, swimming, or cycling.
Weight Management: Losing even a modest amount of weight (5-10% of body weight) can significantly reduce the risk of developing diabetes.
Regular Monitoring: Monitor your blood sugar levels regularly as recommended by your doctor.
Consider Medication: In some cases, your doctor may prescribe medication like metformin to help prevent the progression to type 2 diabetes.
Participate in a Diabetes Prevention Program (DPP): These programs provide education and support to help individuals with prediabetes make lifestyle changes and reduce their risk of developing diabetes.

4. High Blood Sugar (Hyperglycemia)

Definition: Fasting blood sugar 126 mg/dL or higher, A1C 6.5% or higher.

Actions:

Check Blood Sugar More Often: Monitor your blood sugar levels more frequently to understand patterns and triggers.
Adjust Medication: Work with your doctor to adjust your medication (insulin or oral diabetes drugs) as needed.
Review Your Diet: Avoid sugary foods and drinks. Choose complex carbohydrates over simple carbohydrates.
Increase Physical Activity: Engage in more physical activity to help lower blood sugar levels.
Stay Hydrated: Drink plenty of water to help flush out excess glucose.
Check for Ketones: If you have type 1 diabetes and your blood sugar is consistently high, check for ketones using a urine or blood ketone test. High levels of ketones can indicate diabetic ketoacidosis (DKA), a serious condition requiring immediate medical attention.
Contact Your Doctor: If high blood sugar persists or is accompanied by symptoms like increased thirst, frequent urination, blurred vision, or unexplained weight loss, contact your doctor.

When to Seek Emergency Care: Seek immediate medical attention if you experience severe symptoms such as:

Difficulty breathing
Confusion or disorientation
Persistent vomiting
Severe abdominal pain
Loss of consciousness

Target Blood Sugar Ranges for People with Diabetes

The American Diabetes Association (ADA) provides general target blood sugar ranges for most non-pregnant adults with diabetes:

Before meals: 80-130 mg/dL
2 hours after starting a meal: Less than 180 mg/dL
A1C: Less than 7%

It is important to work with your healthcare team to determine your personalized target ranges, as individual goals may vary based on age, health status, and other factors.

Common Mistakes to Avoid

Interpreting blood sugar test results can be tricky. Here are some common mistakes to avoid:

Ignoring Symptoms: Don't dismiss symptoms even if your blood sugar levels appear normal. Symptoms like excessive thirst or frequent urination could indicate underlying issues.
Self-Treating Without Consulting a Doctor: Always consult with a healthcare professional before making significant changes to your medication or treatment plan.
Relying on a Single Test Result: One abnormal result doesn't necessarily mean you have diabetes. Confirm with repeat testing and further evaluation by your doctor.
Not Considering All Factors: Remember that many factors can influence blood sugar levels, including diet, exercise, stress, and medications. Consider these factors when interpreting your results.
Overreacting to Minor Fluctuations: Occasional variations in blood sugar levels are normal. Focus on long-term trends rather than individual readings.
Not Using Proper Testing Techniques: Ensure you are using your blood glucose meter correctly and following the manufacturer's instructions. Improper technique can lead to inaccurate results.
Ignoring the Importance of Regular Monitoring: Regular monitoring of blood sugar levels is crucial for managing diabetes and preventing complications. Don't skip scheduled testing or ignore significant trends in your readings.

Tools and Resources for Blood Sugar Management

Managing blood sugar effectively often requires the right tools and resources. Here are some valuable aids: How To Lower Your Morning Blood Sugar 7 Proven Strategies

Blood Glucose Meter: An essential tool for checking your blood sugar at home. Choose a meter that is easy to use, accurate, and affordable.
Continuous Glucose Monitor (CGM): Provides real-time blood sugar readings throughout the day and night. Useful for tracking trends and making timely adjustments to medication and lifestyle.
Insulin Pump: Delivers insulin continuously throughout the day, mimicking the natural function of the pancreas.
Diabetes Education Programs: Offer education and support to help individuals with diabetes manage their condition effectively. Look for programs accredited by organizations like the American Diabetes Association.
Nutritionist/Dietitian: Can provide personalized meal plans and guidance on healthy eating for diabetes management.
Diabetes Apps: Numerous apps are available to help track blood sugar levels, medication, diet, and exercise.
Online Support Groups: Provide a forum for sharing experiences and getting support from others living with diabetes.
American Diabetes Association (ADA): A leading organization providing information, resources, and support for people with diabetes.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): Offers comprehensive information about diabetes and related conditions.
Healthcare Professionals: Endocrinologists, primary care physicians, certified diabetes educators, and other healthcare professionals can provide expert guidance and support for managing diabetes.

Having access to the right tools and resources can significantly improve your ability to manage your blood sugar levels and overall health.

Conclusion

Reading and understanding your blood sugar test results is a critical skill for anyone managing their health, particularly those with diabetes or prediabetes. By familiarizing yourself with the different types of tests, the normal ranges, and the actions you can take based on your levels, you can make informed decisions and proactively manage your health. Regular monitoring, coupled with lifestyle adjustments and professional guidance, can help you maintain healthy blood sugar levels and prevent long-term complications.