Glucose

Other names: Fasting Blood Glucose, Random blood sugar, Blood sugar level, Fasting blood sugar, Glucose test, Diabetic screening - blood sugar test, Diabetes - blood sugar test

Optimal Result: 65 - 99 mg/dL, or 3.61 - 5.49 mmol/L.

What Is Glucose?

Glucose, often referred to as blood sugar, is the primary source of energy for your body’s cells, including your brain. It comes from the foods you eat—especially carbohydrates like fruit, bread, rice, pasta, and cereal. Once digested, carbohydrates are rapidly broken down into glucose, which enters your bloodstream.

To help your body use glucose effectively, a hormone called insulin (produced by your pancreas) moves glucose from your blood into your cells. When this process doesn’t work properly, glucose builds up in your blood—leading to high blood sugar levels, a hallmark of diabetes.


What Does a Glucose Blood Test Measure?

A glucose blood test measures the amount of glucose circulating in your blood. It’s often included as part of a routine Comprehensive Metabolic Panel (CMP) or Basic Metabolic Panel (BMP).

Why Is This Test Important?

Monitoring blood glucose is essential for detecting:

  • Prediabetes and type 2 diabetes

  • Type 1 diabetes

  • Gestational diabetes (diabetes during pregnancy)

  • Hypoglycemia (low blood sugar)

  • Hyperglycemia (high blood sugar)


Fasting Before a Glucose Test: Do You Need To?

Yes—if your test is part of a fasting blood glucose or CMP, you’ll likely need to fast for 10 to 12 hours before your blood draw. This helps ensure that the result reflects your baseline (fasting) blood sugar, not a temporary increase after eating. Always follow your healthcare provider’s instructions.


Types of Blood Glucose Tests

There are several ways to measure blood glucose:

1. Fasting Blood Sugar (FBS)

  • Taken after you haven’t eaten for 8+ hours.

  • Often used to screen for diabetes or prediabetes.

2. Random Blood Sugar (RBS)

  • Taken at any time, regardless of when you last ate.

  • Used when symptoms of abnormal blood sugar are present.

3. Postprandial Blood Sugar

  • Taken exactly 2 hours after a meal.

  • Often used in people with diabetes to assess insulin response.

4. Oral Glucose Tolerance Test (OGTT)

  • Measures how your body handles glucose over time.

  • Commonly used to diagnose gestational diabetes.

5. Hemoglobin A1c (HbA1c)

  • Reflects your average blood glucose over the past 2–3 months.

  • A key test for diagnosing and monitoring diabetes.


What Is a Normal Blood Glucose Level?

  • Fasting glucose: 70 to 100 mg/dL (3.9–5.6 mmol/L) is considered normal.

  • Random glucose: Typically below 125 mg/dL (6.9 mmol/L), but can vary based on recent food intake.

  • A1c: A result below 5.7% is considered normal.

Your lab report will include reference ranges, but your doctor will interpret results based on your overall health, age, and risk factors.


Symptoms of High vs. Low Blood Glucose

High Blood Sugar (Hyperglycemia) Symptoms:

  • Increased thirst and frequent urination

  • Fatigue

  • Blurred vision

  • Slow-healing wounds

  • Unexplained weight loss

  • Numbness or tingling in the hands or feet

If very high, symptoms can include vomiting, deep breathing, or confusion—seek emergency care, as this may indicate diabetic ketoacidosis (DKA).

Low Blood Sugar (Hypoglycemia) Symptoms:

  • Shaking or trembling

  • Sweating

  • Dizziness or confusion

  • Intense hunger

  • Rapid heartbeat

  • Irritability or anxiety

Severe hypoglycemia can lead to fainting, seizures, or brain damage. Quick treatment with fast-acting carbohydrates like fruit juice or glucose tablets is critical.


Causes of Abnormal Blood Glucose

Elevated Glucose (Hyperglycemia):

  • Diabetes (type 1 or 2)

  • Pancreatic disorders

  • Cushing’s syndrome or adrenal disorders

  • Acute illness or stress in hospitalized patients

Low Glucose (Hypoglycemia):

  • Diabetes medications

  • Liver disease

  • Hormonal deficiencies

  • Insulin-producing tumors (rare)


Diabetes and Blood Glucose Control

Diabetes is a chronic condition where the body has trouble producing or using insulin properly, leading to high blood sugar levels. Over time, uncontrolled diabetes can damage the eyes, kidneys, nerves, and heart.

Risk Factors for Type 2 Diabetes:

  • Age 45 or older

  • Being overweight or obese

  • Family history of diabetes

  • Sedentary lifestyle

  • High blood pressure

  • History of heart disease or stroke

  • Having had gestational diabetes

If you're pregnant, a glucose test is typically performed between 24 and 28 weeks to screen for gestational diabetes.


Bottom Line

Regular monitoring of your glucose levels is key to preventing or managing diabetes and other metabolic conditions. Whether you're fasting for a CMP or checking for symptoms, understanding your glucose results can empower you to make informed health decisions.

Always discuss your lab results with your healthcare provider to understand what’s normal for you.


References

What does it mean if your Glucose result is too high?

What Is Hyperglycemia (High Blood Sugar)?

Hyperglycemia refers to elevated levels of glucose (sugar) in the bloodstream. It is commonly associated with diabetes, but can also result from other health conditions.

Common Symptoms of Hyperglycemia:

  • Increased thirst

  • Frequent urination

  • Blurred vision

  • Slow-healing wounds or frequent infections

These symptoms may develop gradually and can worsen if left untreated.


What Causes High Blood Sugar?

An elevated blood glucose level typically indicates:

  • Type 1 diabetes

  • Type 2 diabetes

  • Prediabetes

  • Gestational diabetes

  • Or in some cases, other medical conditions

Let’s look at each of these more closely:


1. Type 1 Diabetes

  • An autoimmune condition where the body does not produce insulin

  • Often diagnosed in children and young adults

  • Requires lifelong insulin therapy

2. Type 2 Diabetes

  • Occurs when the body becomes resistant to insulin or doesn’t produce enough

  • More common in adults, especially those who are overweight or physically inactive

  • Can often be managed or reversed with lifestyle changes, including weight loss, healthy eating, and regular exercise

3. Prediabetes

  • A condition where blood sugar levels are higher than normal but not yet diabetic

  • Increases your risk of developing type 2 diabetes, heart disease, and stroke

  • Lifestyle changes can significantly reduce the risk of progression

4. Gestational Diabetes

  • A form of diabetes that develops during pregnancy

  • Typically screened between 24 and 28 weeks of pregnancy

  • May occur earlier in women with risk factors for type 2 diabetes

  • Usually resolves after childbirth, but increases the risk of developing type 2 diabetes later in life

If a woman has gestational, type 1, or type 2 diabetes during pregnancy, her healthcare provider will monitor glucose levels closely throughout pregnancy and postpartum to ensure maternal and fetal health.


Other Medical Conditions Linked to High Blood Glucose

Hyperglycemia may also result from non-diabetic conditions, including:

  • Hyperthyroidism (overactive thyroid)

  • Kidney disease

  • Pancreatitis (inflammation of the pancreas)

  • Pancreatic cancer

These conditions may disrupt how insulin is produced or how your body uses glucose, contributing to elevated blood sugar levels.


When to See a Doctor

If you're experiencing symptoms of high blood sugar or have risk factors for diabetes, speak with your healthcare provider about getting a blood glucose test. Early detection and management are key to preventing complications like nerve damage, kidney disease, and cardiovascular problems.

What does it mean if your Glucose result is too low?

Understanding Low Blood Sugar (Hypoglycemia)

Low blood sugar, or hypoglycemia, happens when your blood glucose level drops below 70 mg/dL (3.9 mmol/L). Blood sugar levels naturally fluctuate throughout the day, but when they fall too low, it can become dangerous—especially for people with type 1 diabetes or those taking insulin or certain diabetes medications.

Prompt recognition and treatment are essential to avoid serious complications.


How to Recognize Low Blood Sugar

Knowing the signs of low blood sugar is key to treating it early and preventing it from becoming severe. Symptoms can vary from person to person but may include:

  • Shaking or trembling

  • Sweating or chills

  • Rapid heartbeat

  • Irritability or confusion

  • Dizziness or lightheadedness

  • Intense hunger

  • Anxiety or nervousness

  • Weakness or fatigue

If left untreated, low blood sugar can lead to fainting, seizures, or loss of consciousness.


What Causes Low Blood Sugar?

Several factors can contribute to hypoglycemia, especially in people with diabetes. These include:

  • Taking too much insulin or diabetes medication

  • Skipping meals or not eating enough carbohydrates

  • Exercising more than usual

  • Drinking alcohol, especially without food

  • Delays in meals or unexpected changes in routine

  • Hot, humid weather or being at high altitudes

  • Hormonal changes such as puberty or menstruation

Even people without diabetes can experience low blood sugar under certain conditions.


Types of Low Blood Sugar

1. Reactive Hypoglycemia

Occurs within a few hours after eating and is caused by too much insulin release. Common in people with:

  • Prediabetes

  • A history of stomach surgery

  • Rare enzyme disorders

2. Fasting Hypoglycemia

Occurs after not eating for several hours or overnight. Causes may include:

  • Certain medications (e.g., aspirin, sulfa drugs)

  • Excessive alcohol use

  • Liver, kidney, or adrenal disorders

  • Hormone deficiencies

  • Rare insulin-secreting tumors


Hypoglycemia Unawareness

Some individuals may not feel typical symptoms of low blood sugar. This condition, called hypoglycemia unawareness, makes it harder to detect and treat lows early, increasing the risk of severe episodes.

You may be at higher risk if you:

  • Have had diabetes for over 5–10 years

  • Frequently experience low blood sugar

  • Take beta blockers or other medications that mask symptoms

If you have hypoglycemia unawareness, monitor your blood sugar more often—especially before driving or physical activity.


Nighttime Low Blood Sugar

Low blood sugar can occur while you sleep, especially if you:

  • Had a very active day

  • Exercised close to bedtime

  • Took insulin or other medications at night

  • Drank alcohol in the evening

You might wake up with symptoms like sweating, headache, or confusion—but not always. A Continuous Glucose Monitor (CGM) can alert you during the night if your levels drop too low. Eating a snack before bed can also help prevent overnight lows.


Severe Low Blood Sugar

A blood glucose level below 54 mg/dL (3.0 mmol/L) is considered severely low and can lead to:

  • Slurred speech

  • Trouble walking or seeing

  • Strange behavior or confusion

  • Seizures

  • Fainting or unconsciousness

Severe hypoglycemia is a medical emergency. You may need help from someone else to treat it, including a glucagon injection or emergency medical care.


How to Treat Low Blood Sugar

The 15-15 Rule:

If your blood sugar is between 55–69 mg/dL:

  1. Eat 15 grams of fast-acting carbohydrates (e.g., ½ cup of juice, 4 glucose tablets, or regular soda).

  2. Wait 15 minutes, then recheck your blood sugar.

  3. If still low, repeat the process.

  4. Once back in range, eat a small snack or meal to stabilize your levels.

Important: Young children often need less than 15 grams of carbs. Speak with your child’s healthcare provider for specific guidance.


Preventing Low Blood Sugar

If you have diabetes, you can reduce your risk by:

  • Eating consistent, balanced meals and snacks

  • Timing meals and insulin properly

  • Monitoring your blood sugar as recommended

  • Adjusting food or activity levels based on blood sugar readings

  • Drinking alcohol with food and only in moderation

  • Knowing when your medications are most active (peak action time)

  • Wearing a medical ID bracelet that says you have diabetes

For people without diabetes:

  • Eat small, frequent meals with balanced nutrients (protein, fiber, healthy fats)

  • Limit intake of high-sugar foods

  • Work with your healthcare provider to identify potential causes and treatment


Final Takeaway

Low blood sugar can happen to anyone, but it’s most common among people managing diabetes with insulin or other medications. Learning to recognize your symptoms—and how to respond—can prevent emergencies and help you stay healthy.

If you have frequent lows or symptoms of hypoglycemia unawareness, speak with your doctor. You may need to adjust your treatment plan, diet, or monitoring routine.


References

Frequently asked questions

Healthmatters is a highly-personalized health dashboard.

Instead of searching for your lab results in different places or tracking them down from different providers, Healthmatters houses, organizes, and interprets them all in one central location.

With a Healthmatters account, you can dive into the details of each biomarker and gain insights into the meaning behind your medical test data, anytime, anywhere.

For our professional users, Healthmatters provides intuitive tools that not only streamline analysis but also save valuable time when delving into your client's lab report history.

Healthmatters.io personal account provides in-depth research on 4000+ biomarkers, including information and suggestions for test panels such as, but not limited to:

  • The GI Effects® Comprehensive Stool Profile,
  • GI-MAP,
  • The NutrEval FMV®,
  • The ION Profile,
  • Amino Acids Profile,
  • Dried Urine Test for Comprehensive Hormones (DUTCH),
  • Organic Acids Test,
  • Organix Comprehensive Profile,
  • Toxic Metals,
  • Complete Blood Count (CBC),
  • Metabolic panel,
  • Thyroid panel,
  • Lipid Panel,
  • Urinalysis,
  • And many, many more.

You can combine all test reports inside your Healthmatters account and keep them in one place. It gives you an excellent overview of all your health data. Once you retest, you can add new results and compare them.

If you are still determining whether Healthmatters support your lab results, the rule is that if you can test it, you can upload it to Healthmatters.

While we work with many popular labs, we welcome reports from lots of other places too.

It's as simple as this: if you can get a test done, you can upload it to Healthmatters and we can interpret results from any lab out there. If laboratories can analyze it, we can interpret it.

If you’re on the hunt for a specific biomarker, contact us and we'll add it to our database. Anything from blood, urine, saliva, or stool can be uploaded, understood, and tracked with your Healthmatters account.

There are two ways to add your test reports to your Healthmatters account. One option is to input the data using the data entry forms. The other method is to utilize our "Data entry service."

Our data entry forms offer an easy, fast, and free way for you to input the reports yourself. Self-entry allows you to add an unlimited number of reports at no cost. We make the self-entry process user-friendly, providing dozens of templates that pre-populate the most popular laboratory panels and offering instant feedback on entered values.

For those who prefer assistance, we offer a "Data entry service" to help you input your data. Simply attach an image or file of your lab test results, and a qualified team member from our data entry team will add the results for you.

We support various file types, including PDFs, JPGs, or Excel. This service is particularly useful if you have many reports to upload or if you're too busy to handle the data entry yourself.

Our special data entry service makes it easy to add your results to your private dashboard. Just attach an image or a file of your lab test results, and our skilled data entry team will do the work for you. It's all done by humans, ensuring that your data is entered accurately and with personal care for each client.

Depending on your account, the data entry service can be included for free or come at an additional cost of $15 per report.

For users on the Complete monthly plan, the first report is entered free of charge, and each additional report incurs a fee of $15.

Unlimited account holders enjoy the entry of ten reports without charge. Subsequent reports are subject to a $15 fee per report.

Additionally, users on the Complete plan can upgrade to a yearly subscription from the account settings. The annual subscription includes a data entry service for five reports.

The Unlimited plan is a one-time purchase for $250, and it covers your account for a lifetime with no additional payments.

For the Complete plan, the cost is $15 per month. You have the flexibility to cancel it anytime through your account settings, ensuring no further payments. To avoid charges, remember to cancel at least a day before the renewal date. Once canceled, the subscription remains active until the end of the current billing cycle.

Additionally, you can upgrade to the yearly Advanced plan from within your account. The annual cost is $79, and it comes with a data entry service for five reports.

You can always upgrade to a lifetime version with a prorated price from a monthly or yearly subscription.

Simply log in and navigate to your account settings to cancel your subscription. Scroll down to locate the 'Cancel' button at the bottom of the page. Ensure you cancel at least one day before the renewal date to prevent any charges. Once cancellation is requested, the subscription remains active until the conclusion of the current billing cycle.

Our goal has been to make your Healthmatters account as intuitive as possible.

We’ve crafted multiple ways for you to navigate your data, whether you're glancing at a single report or delving into your historical test reports.

1. Graph View:

Dive into a visual journey with our biomarker graphs, showcasing over 40 data points. Combining years of results unveils trends, empowering you to make informed decisions. Our visualization tools make it a breeze to compare and understand changes over time, even if your results are from different labs. A search function and filters simplify the exploration of extensive data, allowing you to focus on what needs attention.

2. All Tests View

Explore neatly organized reports on a timeline, highlighting crucial details like dates, critical results, and lab/panel names. Each report opens up to reveal in-depth descriptions and additional recommendations for each biomarker. The history of previous results is just a click away, and you can download a comprehensive report for deeper insights. Color-coded and user-friendly, it's designed for easy reading, understanding, and navigation.

3. Table View:

For a holistic view of all biomarkers side by side, our table view is your go-to. Results are neatly displayed in a categorized and dated table, ideal for those with an extensive test history. Utilize sorting, filters, and color-coding to enhance your analysis and gain extra insights.

Yes, you can download information from your account. We can compile your labs into a CSV file. To download all your labs, you can go to Account Settings, and at the bottom of the page, you will find a link to download your information.

Yes, you can print your report. To do so, navigate to "All tests" and open the report you wish to print. You'll find a print button in the right corner of the report. Click on it, and your browser's print window will open. If you prefer to print in a bigger typeface, adjust the scale using the print window settings.

Yes, you can! We highly recommend activating Two-Factor Authentication (2FA) for your account. To do so, please navigate to the "Profile and Security" section of your account, where you will find instructions for activating 2FA.

Yes, you can. When entering values for the biomarker, you will see an "Edit Range" button. Click this button, and you'll have the option to enter a custom range.

A personal account is all about keeping your own lab test results in check. It's just for you and your personal use.

The professional account is designed for health professionals who wish to track and organize their clients' laboratory results.

Yes, you can! Simply go to the "Invite Doctor" section, enter your doctor’s email address, and send the invitation. Your doctor will receive an email with secure access to view your results. You can revoke this access at any time. All shared information is securely encrypted and protected for your privacy.
Yes, you can! Go to the Graph view or Spreadsheet view. In the top-right corner, click "Export to Excel," and the file will be downloaded to your device.

Use promo code to save 10% off any plan.


We implement proven measures to keep your data safe.

At HealthMatters, we're committed to maintaining the security and confidentiality of your personal information. We've put industry-leading security standards in place to help protect against the loss, misuse, or alteration of the information under our control. We use procedural, physical, and electronic security methods designed to prevent unauthorized people from getting access to this information. Our internal code of conduct adds additional privacy protection. All data is backed up multiple times a day and encrypted using SSL certificates. See our Privacy Policy for more details.