Blood glucose vs plasma glucose- what is the difference?
If you have ever had a blood test, you may have noticed that your results include both blood glucose and plasma glucose levels. But what is the difference between the two? Are they interchangeable, or do they indicate different things?
Blood glucose and plasma glucose are both important indicators of blood sugar levels, but they are not the same thing. Understanding the difference between the two can help you better understand your own health and how to manage conditions like diabetes.
In this article, we will explore the differences between blood glucose and plasma glucose, including how they are measured, what they indicate about your health, and why it’s important to monitor both. Whether you are managing a chronic condition or simply curious about your own health, this information can help you make informed decisions about your well-being.
What is Blood Glucose?
Blood glucose, also commonly known as blood sugar, is the amount of glucose present in the blood. Glucose is a type of sugar that is used by the body as a source of energy to fuel various bodily functions like breathing, movement, and even brain activity.
When we consume food, the carbohydrates in the food are broken down into glucose, which then enters the bloodstream. The pancreas, a gland located behind the stomach, produces insulin, a hormone that helps the body utilize glucose as energy and lowers blood glucose levels when they get too high.
Maintaining healthy blood glucose levels is crucial for overall health, as both high and low blood glucose levels can cause serious health complications. High blood glucose levels over time can lead to a diagnosis of diabetes, while severe low blood glucose levels can cause seizures and unconsciousness.
Blood glucose levels are measured in milligrams per deciliter (mg/dL) in the United States and millimoles per liter (mmol/L) in other countries. The American Diabetes Association recommends target blood glucose levels between 80-130 mg/dL before meals and less than 180 mg/dL two hours after meals for people with diabetes.
To measure blood glucose levels, a drop of blood is typically taken from the fingertip using a lancet device and applied to a glucose meter. Alternatively, blood glucose levels can be measured using a continuous glucose monitoring system, which involves a small sensor inserted under the skin that continuously measures glucose levels and sends the information to a receiver.
What is Plasma Glucose?
Plasma glucose, also known as blood glucose or blood sugar, is a type of glucose that’s found in the liquid portion of blood known as plasma. Like other forms of glucose, plasma glucose is a vital source of energy for the body’s cells and plays a critical role in maintaining overall health.
Plasma glucose levels are often used as a diagnostic tool for certain medical conditions, most notably diabetes. In people with diabetes, the body either does not produce enough insulin or is unable to use insulin effectively. As a result, glucose levels in the blood can become elevated and lead to a range of health complications.
To measure plasma glucose levels, a blood sample is typically collected from the arm and sent to a laboratory for analysis. Unlike other glucose tests, such as an oral glucose tolerance test, plasma glucose tests do not require the ingestion of glucose beforehand.
Interpretation of plasma glucose levels can vary depending on a person’s age, gender, and overall health status. In general, normal plasma glucose levels range between 70 and 99 milligrams per deciliter (mg/dL) when fasting and less than 140 mg/dL two hours after meals.
However, if plasma glucose levels are consistently above this range, it may be indicative of underlying medical conditions such as pre-diabetes or diabetes. Healthcare providers may also use plasma glucose testing to monitor the effectiveness of diabetes treatments and adjust medication dosages accordingly.
Difference between Blood Glucose and Plasma Glucose
Understanding the difference between blood glucose and plasma glucose is crucial for individuals with diabetes and those at risk for developing the condition. Both blood and plasma glucose levels can provide valuable information about a person’s health, but they are not the same.
Blood glucose levels refer to the concentration of glucose, or sugar, in the blood. This measurement takes into account both glucose that is freely circulating in the bloodstream as well as that which is contained within red blood cells. Blood glucose levels can be measured using a glucose meter and a drop of blood from a finger prick.
On the other hand, plasma glucose levels refer only to the concentration of glucose that is suspended in the liquid portion of the blood, or plasma. Plasma glucose levels are typically measured by collecting a blood sample from a person’s arm and sending it to a laboratory for analysis.
Why is this distinction important? The water content of blood and plasma is different, and as a result, the concentration of glucose in plasma is slightly higher than in whole blood. This means that if a person were to measure their blood glucose level with a glucose meter and then measure their plasma glucose level with a laboratory test, the plasma glucose level would be slightly higher.
Furthermore, since glucose is transported by the bloodstream to different parts of the body as a source of energy, variations in how glucose is transported can also affect the readings. Plasma glucose levels are generally the preferred measure for medical diagnosis and management because they offer a more accurate representation of the concentration of glucose in the bloodstream.
Causes of Variation in Glucose Levels
Blood glucose levels fluctuate throughout the day, rising after meals and falling during periods of physical activity. However, certain factors can also cause significant variations in glucose levels, which may be cause for concern for individuals with diabetes or those at risk for developing the condition.
1. Food and Beverage Intake: The consumption of carbohydrates, particularly those with a high glycemic index, can cause a rapid rise in blood glucose levels. Conversely, foods with a lower glycemic index, such as whole grains, are absorbed more slowly, resulting in more stable glucose levels. Beverages such as alcohol and sweetened drinks can also cause significant elevations in blood glucose levels.
2. Physical Activity: Exercise stimulates glucose uptake by the muscles, leading to a decrease in blood glucose levels. However, the duration and intensity of physical activity can affect glucose levels, with prolonged or intense exercise causing a drop in blood glucose and short bursts of activity causing a temporary rise.
3. Medications: Certain medications, including steroids, diuretics, and beta-blockers, can alter glucose levels by affecting insulin secretion and insulin sensitivity. Additionally, some medications used to treat diabetes can cause hypoglycemia, or low blood glucose levels, if not taken properly.
4. Stress: Emotional or physical stress can trigger the release of hormones that increase blood glucose levels, including cortisol and adrenaline. Chronic stress or anxiety can also lead to insulin resistance, making it more difficult for the body to regulate glucose levels.
5. Illness or Infection: When the body is fighting an illness or infection, it releases hormones that stimulate glucose production in the liver and decrease insulin sensitivity, leading to elevated blood glucose levels.
Understanding the potential causes of variation in glucose levels is important for individuals with diabetes or those at risk for the condition. Regular monitoring of glucose levels and working with healthcare providers can help manage these fluctuations and reduce the risk of associated health complications.
Diagnosis of Diabetes with Blood and Plasma Glucose Tests
Diabetes is a serious health condition that can lead to various complications if left untreated. The diagnosis of diabetes is typically based on blood glucose levels, which measure the amount of glucose in the bloodstream. There are two commonly used methods for measuring glucose levels – blood glucose tests and plasma glucose tests.
Blood glucose tests involve taking a small amount of blood from a finger prick and measuring the glucose concentration in the sample using a glucose meter. The measurement indicates the glucose levels present in the fluid part of the blood, which is known as serum or plasma.
Blood glucose tests are convenient and can be conducted in a clinical setting or at home using a glucose meter. However, the results of blood glucose tests can be affected by a variety of factors, including food intake, exercise, and stress. Therefore, it is essential to follow the recommended guidelines for fasting and food intake before taking a blood glucose test.
Plasma glucose tests involve taking a blood sample from a vein and separating the plasma from the blood cells using a centrifuge. The glucose concentration in the plasma is then measured using an enzymatic method or glucose oxidase. Plasma glucose tests provide more accurate results because they measure the glucose levels in the blood’s liquid component, rather than the blood cells’ content. Plasma glucose tests are typically used for oral glucose tolerance tests or during pregnancy to screen for gestational diabetes.
The American Diabetes Association recommends a fasting plasma glucose test or an oral glucose tolerance test for diagnosing diabetes. A fasting plasma glucose test measures the glucose level after an eight-hour fast, while the oral glucose tolerance test measures the glucose level in response to a glucose drink after an overnight fast. Both tests provide a criterion for diabetes diagnosis, with a fasting plasma glucose level of 126 mg/dL or higher or an oral glucose tolerance test result of 200 mg/dL or higher indicating diabetes.
Diabetes is a chronic disease that requires ongoing monitoring of blood glucose levels to manage effectively. People with diabetes should work closely with their healthcare providers and diabetes educators to develop a personalized management plan that includes regular blood glucose monitoring, medication management, and lifestyle modifications. By staying informed about their blood glucose levels, people with diabetes can take proactive steps to prevent complications and maintain their overall health.
