Glucose, Plasma

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Also known as: Glucose Plasma

Glucose, Plasma

A blood glucose test measures the amount of a sugar called glucose in a sample of your blood. Glucose is a major source of energy for most cells of the body, including those in the brain. The hormones insulin and glucagon help control blood glucose levels.
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The Glucose, Plasma test contains 1 test with 1 biomarker.

Brief Description: The Glucose Plasma test, also known as a fasting blood sugar test, is a common laboratory test used to measure the concentration of glucose (sugar) in the blood. Glucose is the primary source of energy for the body's cells and is essential for normal bodily functions.

Also Known As: Fasting Blood Glucose Test, FBG Test, Fasting Blood Sugar Test, FBS Test, Fasting Glucose Test, FG Test

Collection Method: Blood Draw

Specimen Type: Plasma

Test Preparation: Fasting required

When is a Glucose Plasma test ordered?

Diabetes screening is recommended by several health groups, including the American Diabetes Association and the United States Preventive Services Task Force, when a person is 45 years old or has risk factors.

The ADA recommends retesting within three years if the screening test result is within normal limits, but the USPSTF recommends testing once a year. Annual testing may be used to monitor people with prediabetes.

When someone exhibits signs and symptoms of high blood glucose, a blood glucose test may be conducted.

Diabetics are frequently asked to self-check their glucose levels multiple times a day in order to monitor glucose levels and choose treatment alternatives as suggested by their doctor. Blood glucose levels may be ordered on a regular basis, along with other tests such as A1c, to track glucose control over time.

Unless they show early symptoms or have had gestational diabetes in a prior pregnancy, pregnant women are routinely screened for gestational diabetes between the 24th and 28th week of pregnancy. If a woman is at risk of type 2 diabetes, she may be tested early in her pregnancy, according to the American Diabetes Association. When a woman has type 1, type 2, or gestational diabetes, her health care provider will normally order glucose levels to monitor her condition throughout the duration of her pregnancy and after delivery.

What does a Glucose Plasma blood test check for?

A fasting glucose test measures glucose. Glucose is the major energy source for the body's cells and the brain and nervous system's only source of energy. A consistent supply must be provided, and a somewhat constant level of glucose in the blood must be maintained. The glucose level in the blood can be measured using a variety of methods. 

Fruits, vegetables, breads, and other carbohydrate-rich foods are broken down into glucose during digestion, which is absorbed by the small intestine and circulated throughout the body. Insulin, a hormone generated by the pancreas, is required for the use of glucose for energy production. Insulin promotes glucose transport into cells and instructs the liver to store surplus energy as glycogen for short-term storage or triglycerides in adipose cells.

Normally, blood glucose rises slightly after you eat or drink, and the pancreas responds by releasing insulin into the blood, the amount of which is proportional to the size and substance of the meal. The level of glucose in the blood declines as glucose enters the cells and is digested, and the pancreas responds by delaying, then ceasing the secretion of insulin.

When blood glucose levels fall too low, such as between meals or after a strong activity, glucagon is released, which causes the liver to convert some glycogen back into glucose, so boosting blood glucose levels. The level of glucose in the blood remains pretty steady if the glucose/insulin feedback loop is working appropriately. When the balance is upset and the blood glucose level rises, the body strives to restore it by boosting insulin production and removing excess glucose through the urine.

Several diseases can cause the equilibrium between glucose and pancreatic hormones to be disrupted, resulting in high or low blood glucose. Diabetes is the most common cause. Diabetes is a collection of illnesses characterized by inadequate insulin production and/or insulin resistance. Untreated diabetes impairs a person's ability to digest and utilize glucose normally. Type 1 diabetes is diagnosed when the body is unable to produce any or enough insulin. People with prediabetes or type 2 diabetes are insulin resistant and may or may not be able to produce enough of the hormone.

Organ failure, brain damage, coma, and, in extreme situations, death can result from severe, sudden fluctuations in blood glucose, either high or low. Chronically high blood glucose levels can harm body organs like the kidneys, eyes, heart, blood vessels, and nerves over time. Hypoglycemia can harm the brain and nerves over time.

Gestational diabetes, or hyperglycemia that exclusively arises during pregnancy, can affect some women. If left untreated, this can result in large babies with low glucose levels being born to these mothers. Women with gestational diabetes may or may not acquire diabetes later in life.

Lab tests often ordered with a Glucose Plasma test:

When a Plasma Glucose test is ordered, it's often part of a broader evaluation of metabolic health and diabetes management. Here are some tests commonly ordered alongside it:

  1. Hemoglobin A1c (HbA1c):

    • Purpose: To measure the average blood glucose levels over the past two to three months.
    • Why Is It Ordered: To provide a longer-term view of blood glucose control, crucial for diagnosing and monitoring diabetes.
  2. Fasting Lipid Profile:

    • Purpose: To measure levels of cholesterol and triglycerides.
    • Why Is It Ordered: To assess cardiovascular risk, as diabetes and dyslipidemia often coexist.
  3. Microalbumin:

    • Purpose: To detect small amounts of albumin in the urine.
    • Why Is It Ordered: To check for early signs of diabetic kidney disease.
  4. C-Peptide Test:

    • Purpose: To measure the level of C-peptide, which is released when the body produces insulin.
    • Why Is It Ordered: To evaluate how much insulin the body is producing and to help distinguish between type 1 and type 2 diabetes.
  5. Kidney Function Test:

    • Purpose: To evaluate kidney function.
    • Why Is It Ordered: To assess for diabetic nephropathy and other kidney problems common in diabetes.
  6. Liver Function Test:

    • Purpose: To assess liver health.
    • Why Is It Ordered: To evaluate for non-alcoholic fatty liver disease and other liver conditions associated with metabolic syndrome and diabetes.
  7. Thyroid Function Test:

    • Purpose: To evaluate thyroid function.
    • Why Is It Ordered: Because thyroid disorders can affect metabolism and are more common in individuals with diabetes.
  8. Fructosamine:

    • Purpose: To provide an average of blood glucose levels over the past 2-3 weeks.
    • Why Is It Ordered: To complement HbA1c for patients with fluctuating glucose levels or in situations where HbA1c may be unreliable.

These tests, when ordered alongside a Plasma Glucose test, provide a comprehensive view of an individual’s metabolic health and diabetes management. They are crucial for accurately diagnosing and effectively managing diabetes, assessing the risk of complications, and monitoring the impact of treatment on different organ systems. The specific combination of tests will depend on the individual’s symptoms, risk factors, treatment regimen, and overall health status.

Conditions where a Glucose Plasma test is recommended:

The Glucose Plasma test is crucial for diagnosing and managing diabetes. It's also used to monitor glucose levels in people with prediabetes and those at risk of developing diabetes.

How does my health care provider use a Glucose Plasma test?

The blood glucose test can be used for a variety of purposes, including:

  • Detect hyperglycemia and hypoglycemia
  • Screen for diabetes in those who are at risk before symptoms appear; there may be no early indications or symptoms of diabetes in some circumstances. As a result, screening can aid in detecting it and allowing treatment to begin before the illness worsens or complications emerge.
  • Aid in the detection of diabetes, prediabetes, and gestational diabetes.
  • Monitor your blood sugar levels and manage your diabetes

Glucose levels should be monitored in those who have been diagnosed with diabetes.

Between the 24th and 28th week of pregnancy, glucose blood tests are performed to assess pregnant women for gestational diabetes. Pregnant women who have never been diagnosed with diabetes should be screened and diagnosed using either a one-step or two-step strategy, according to the American Diabetes Association and the US Preventive Services Task Force.

Other tests, including diabetic autoantibodies, insulin, and C-peptide, may be used in conjunction with glucose to assist in detecting the reason of elevated glucose levels, differentiate between type 1 and type 2 diabetes, and assess insulin production.

What does my glucose test result mean?

High blood glucose levels are most commonly associated with diabetes, but they can also be caused by a variety of other diseases and ailments.

Hypoglycemia is defined by a drop in blood glucose to a level that triggers nervous system symptoms before affecting the brain. The Whipple triad is a set of three criteria for diagnosing hypoglycemia.

Most Common Questions About the Glucose Plasma test:

Clinical Utility and Interpretation

What is the Glucose Plasma test and why is it significant?

The Glucose Plasma test measures the concentration of glucose in the blood, specifically in the plasma component. It's a fundamental test to diagnose and manage diabetes mellitus and other carbohydrate metabolism disorders. Maintaining appropriate glucose levels is crucial for overall health since both high and low levels can lead to severe health issues.

How are the results of the Glucose Plasma test interpreted for diagnosing diabetes?

For a fasting Glucose Plasma test, results are typically interpreted as:

  • Normal: Below 99 mg/dL
  • Prediabetes (impaired fasting glucose): 100-125 mg/dL
  • Diabetes: 126 mg/dL or higher on two separate occasions

However, interpretations can vary based on specific conditions, patient's age, and other considerations. Other tests, like the oral glucose tolerance test or Hemoglobin A1c, may also be used in conjunction with the plasma glucose levels to diagnose diabetes.

Clinical Applications and Diagnoses

In which scenarios is the Glucose Plasma test typically ordered?

The Glucose Plasma test is typically ordered when someone has symptoms suggestive of high blood sugar (hyperglycemia) such as increased thirst, frequent urination, fatigue, and blurred vision. It's also routinely performed as part of general health screenings, especially in individuals with risk factors for diabetes.

How does the Glucose Plasma test help in monitoring and managing diabetes?

Regular monitoring of glucose levels allows individuals with diabetes and their healthcare providers to assess the effectiveness of treatment strategies, whether that includes lifestyle modifications, oral medications, or insulin therapy. Adjustments can be made based on these results to achieve and maintain target glucose levels.

Comparative Insights

How does the Glucose Plasma test differ from the Hemoglobin A1c test?

While the Glucose Plasma test measures the current concentration of glucose in the blood, the Hemoglobin A1c test reflects the average blood sugar levels over the past 2 to 3 months. The Hemoglobin A1c test measures the percentage of glucose that's attached to the hemoglobin protein in red blood cells. Both tests have their unique advantages and are often used complementarily in the management of diabetes.

Understanding Limitations and Challenges

What are some of the limitations of the Glucose Plasma test?

While the Glucose Plasma test provides a snapshot of the glucose levels at the time of the test, it doesn't offer insight into glucose fluctuations throughout the day or how levels might change after meals. Also, various factors like recent carbohydrate intake, stress, illness, or exercise can influence glucose levels, potentially leading to non-representative readings during a single test.

How do other conditions apart from diabetes affect the results of the Glucose Plasma test?

Conditions other than diabetes can influence blood glucose levels. For instance, certain tumors, endocrine disorders, liver diseases, or medications might cause elevated glucose levels. Conversely, some conditions like prolonged fasting, liver diseases, or insulin-producing tumors can cause decreased glucose levels. It's essential to interpret the test results in the context of the individual's overall health and other diagnostic findings.

Additional Questions and Insights

If a person's Glucose Plasma test results are borderline, what might be the next step?

If the Glucose Plasma test results are in the borderline range, indicating prediabetes, healthcare providers might recommend lifestyle modifications to prevent the progression to diabetes. They might also order further tests, such as the oral glucose tolerance test or the Hemoglobin A1c, to gather more information on glucose metabolism.

Can stress impact the results of the Glucose Plasma test?

Yes, stress, whether physical (like illness or injury) or emotional, can increase the body's secretion of stress hormones like cortisol and adrenaline. These hormones raise blood sugar levels. Therefore, it's possible for acute or chronic stress to affect Glucose Plasma test results.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

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