I. Introduction

Although all three forms of diabetes have different causes, they have the same end result. Too much glucose builds up in the bloodstream, causing symptoms such as excessive thirst, frequent urination, unexplained weight loss, and fatigue. According to the Centers for Disease Control and Prevention, approximately 30 million Americans have diabetes. The majority of these people, 90 to 95%, have Type 2 diabetes. Only about 5% of people with diabetes have Type 1. The CDC also estimates that gestational diabetes affects 2% to 10% of pregnancies in the United States each year.

This guide focuses on the use of glucose testing to diagnose and monitor patients with Type 2 diabetes. It explains how glucose testing works, why the test is necessary, and how to prepare for the test. The guide also provides an overview of Type 2 diabetes, including the most common symptoms and treatment options.

II. Overview of the Glucose Test

Why to get tested

The purpose of the glucose test is to determine if a person’s glucose level is too high or too low. Glucose testing is used in the diagnosis and management of several health conditions, including liver disease, hyperthyroidism, and kidney disease, but it is most often used to diagnose diabetes or monitor the effects of diabetes treatment.

When to get Tested

According to MedlinePlus and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), glucose testing is recommended at the following times:

  • Any time an individual has the symptoms of high blood sugar, including slow-healing wounds, blurred vision, excessive thirst, fatigue, or frequent urination
  • Any time an individual has the symptoms of low blood sugar, including hunger, confusion, anxiety, sweating, or trembling
  • Following the identification of diabetes risk factors such as obesity, high blood pressure, or a history of heart disease
  • Sometime between the 24th and 28th week of pregnancy
  • First thing in the morning, before meals, two hours after meals, and at bedtime for people who have already been diagnosed with diabetes

How Testing Works

The blood glucose test is performed on a small sample of blood drawn from a vein. Preparation requirements depend on whether the doctor has ordered a fasting glucose test or a random glucose test. For the fasting version, the patient must not eat or drink anything other than water for approximately 8 to 12 hours before the test. The random glucose test does not require fasting or any other type of preparation.

III. The Basics of Type 2 Diabetes

Type 2 diabetes, sometimes called adult-onset diabetes, develops when the body does not produce insulin or is unable to use insulin effectively. In healthy people, insulin helps glucose (blood sugar) enter the cells. Once glucose enters the cells, it is either used immediately as a source of energy or stored for future energy needs. In people with Type 2 diabetes, a lack of insulin causes glucose to build up in the bloodstream instead of entering the cells. Elevated glucose levels are responsible for symptoms such as excessive thirst, blurred vision, sudden weight loss, fatigue, excessive hunger, and urinating more often than usual.

Some people have a higher risk of developing Type 2 diabetes than others. The condition is common in older people, individuals who are overweight or obese, and people who live a sedentary lifestyle. Someone who is sedentary spends a lot of time sitting or lying down and little to no time exercising. The risk of Type 2 diabetes is also higher for people who have a family history of the disease.

Left untreated, Type 2 diabetes can cause serious complications. People with diabetes are twice as likely as people without diabetes to develop heart disease or have a stroke, according to the Centers for Disease Control and Prevention. The reason people with Type 2 diabetes are prone to developing heart conditions is that high levels of blood glucose damage the body’s nerves and blood vessels. Over time, damage to the blood vessels can cause high blood pressure, which damages the walls of the arteries, the vessels that carry oxygen-rich blood away from the heart and deliver it to other organs.

Damage to the nerves can result in a lack of feeling in one or both feet, making it difficult for a person with Type 2 diabetes to recognize when a wound is forming. Additionally, damage to the blood vessels can cause poor circulation, which causes foot ulcers and other wounds to heal slowly. If a foot ulcer becomes infected and fails to heal properly, it may be necessary to amputate the affected foot. The American Podiatric Medical Association (APMA) reports that 14% to 24% of the people with diabetes who develop foot ulcers will have to undergo an amputation at some point in their lives.

Type 2 diabetes can also cause a condition called diabetic nephropathy, which develops when high levels of glucose result in kidney damage. The kidneys are responsible for maintaining normal fluid levels and filtering wastes from the blood. In people with kidney damage, fluid and waste products build up in the blood, which can cause swelling, bloody urine, frequent urination, foamy urine, and fatigue. In severe cases, kidney disease may progress to end-stage renal disease, which can be fatal without hemodialysis or a kidney transplant. Hemodialysis is a mechanical process used to remove blood from the body, filter it, and then return it to the patient’s bloodstream.

IV. How a Glucose Test Works

Glucose, often called “blood sugar,” is the most common type of sugar in the body. In people who have not been diagnosed with diabetes, the glucose test is used to determine if an individual has a normal amount of glucose in the blood. For people who have already been diagnosed with diabetes, the glucose test is used to determine if an individual’s treatment plan is working to reduce high glucose levels. Based on the results of the test, the patient’s medical provider may adjust medication dosages or make different recommendations regarding diet and exercise.

Glucose is one of the most important substances in the human body, as it is a major source of energy for the brain and other organs. Any time an individual eats something containing carbohydrates, the carbohydrates are broken down into glucose, and the pancreas releases insulin to help the glucose enter the body’s cells. In people with Type 2 diabetes, there is not enough insulin available, causing glucose to build up in the bloodstream. The glucose test helps determine if a person’s glucose level is too high or too low, which can indicate the presence of Type 2 diabetes and other medical conditions.

The two most common types of glucose testing are the fasting plasma glucose test and the random plasma glucose test. For a fasting test, the patient must fast for at least eight hours before having a blood sample drawn. The fasting test is typically performed in the morning. A diagnosis of diabetes is usually made if a person’s fasting glucose result is greater than or equal to 126 mg/dl (milligrams per deciliter). For a random plasma glucose test, the patient does not need to fast. The test can be performed at any time of the day. A diagnosis of diabetes is usually made if a person’s random glucose result is greater than or equal to 200 mg/dl.

Glucose testing requires a small blood sample to be drawn from the patient’s vein, a procedure known as venipuncture. Before drawing blood, a phlebotomist cleans the skin with alcohol or another antiseptic. A tourniquet is usually placed around the upper arm, causing the vein to swell, which makes it easier for the person drawing the blood to determine where to insert the needle. Once the needle is in the vein, blood is collected in a small container until the sample is large enough to use for testing. Finally, the phlebotomist removes the needle from the patient’s arm and covers the venipuncture site with a bandage.

Glucose tests are typically performed in hospitals, medical clinics, and laboratories, but home testing is also an option. In fact, Type 2 diabetics must check their glucose levels several times per day to make sure they don’t have too much glucose in their bloodstreams. It’s also possible to order a testing kit from an independent laboratory, take the blood sample at home, and send the sample to the laboratory for analysis.

Home glucose test kits are often used by individuals who already have a diabetes diagnosis and are currently on treatment medications. They usually include testing strips, lancets for finger-sticks, and a blood glucose meter. Patients can test blood glucose at home using a small amount of blood obtained from a finger prick. Their doctor will instruct how many times a day testing is necessary.

V. Treatment for Type 2 Diabetes

The main treatments for Type 2 diabetes include lifestyle changes and medications. Not every case of diabetes is the same, so it is important to have a licensed medical professional, such as a doctor or physician assistant, develop a customized treatment plan. Dietary changes are a key component of diabetes treatment, as glucose levels typically increase when a diabetic consumes foods and beverages containing carbohydrates. Therefore, MedlinePlus recommends that people with Type 2 diabetes eat roughly the same amount of carbohydrates at every meal. It is also important for diabetics to eat healthy fats, consume fewer calories at each meal, and eat a variety of foods from all the major food groups. Some beverages, such as milk and soda, have high carbohydrate levels, so switching to water and other calorie-free drinks can help Type 2 diabetics keep their glucose levels under control.

According to the American Diabetes Association, regular exercise makes the body more responsive to insulin, which can result in reduced glucose levels. Regular physical activity also improves blood pressure and circulation, helps with weight control, and may help people with diabetes sleep better. The NIDDK advises people with Type 2 diabetes to engage in at least 30 minutes of physical activity five days per week. For best results, the activity should be performed at a moderate or vigorous level. In people who are overweight or obese, it may be necessary to engage in at least 60 minutes of moderate or vigorous physical activity per week, according to the NIDDK.

For some people, lifestyle changes are enough to keep glucose levels in check. Other people may have to combine their lifestyle changes with medications to prevent their glucose levels from getting too high. One of the most common medications is called metformin, and it helps diabetics by making the body more sensitive to insulin and reducing the amount of glucose produced by the liver. If an individual’s glucose levels are still too high even after starting oral medications, it may be necessary to take injectable insulin, which is available in rapid-acting, short-acting, intermediate-acting, and long-acting forms. Rapid-acting insulin starts working within 15 minutes of an injection, but it only lasts for two to four hours. In contrast, long-acting insulin takes several hours to work, but it lasts for 24 hours or more.

VI. Frequently Asked Questions

Q: What causes Type 2 diabetes?

A: Type 2 diabetes is caused by insufficient insulin production. In humans, the pancreas contains specialized cells responsible for making insulin. These cells are known as islet cells. Some Type 2 diabetics produce insulin in insufficient quantities, while others produce no insulin at all. Although not all people with Type 2 diabetes are inactive, overweight, or obese, a sedentary lifestyle does increase the risk for this condition.

Q: What is a normal fasting glucose level?

A: According to the Centers for Disease Control and Prevention, a person’s fasting glucose level is considered normal when it is below 99 mg/dl. People with fasting glucose levels ranging from 100 to 125 mg/dl are considered prediabetic. Type 2 diabetes is diagnosed when an individual’s fasting glucose level is greater than or equal to 126 mg/dl.

Q: What is prediabetes?

A: Prediabetes is a medical condition in which a person’s glucose levels are elevated without being high enough for a diagnosis of Type 2 diabetes. Getting diagnosed with prediabetes is an opportunity to make lifestyle changes that can prevent the condition from turning into Type 2 diabetes.

Q: Does the glucose test hurt?

A: To perform a glucose test, a laboratory needs a sample of the patient’s blood. This sample is obtained by inserting a needle into one of the patient’s veins. When the needle is inserted, it’s normal to feel a slight prick, but the blood draw should not be painful.

Q: Why do you have to fast for a glucose test?

A: Eating any food or drink containing carbohydrates can cause glucose levels to rise, as carbohydrates are broken down into glucose once they’re consumed. To ensure an accurate test result, it’s important to fast for eight to 12 hours before a random plasma glucose test, which means no eating or drinking anything other than plain water.

Q: Is Type 2 diabetes serious?

A: Yes, Type 2 diabetes is a serious medical condition. Without treatment, Type 2 diabetes can cause a variety of complications, including blindness, kidney disease, high blood pressure, foot ulcers, and an increased risk for stroke and heart attack. The condition also causes several unpleasant symptoms, such as fatigue, frequent urination, and excessive thirst.

Q: How often do I need to check my glucose levels if I have been diagnosed with Type 2 diabetes?

A: Not all Type 2 diabetics test their glucose levels the same number of times each day. Individuals who use insulin may need to check their glucose levels more frequently than people who do not use insulin, for example. It’s common for people with Type 2 diabetes to check their glucose levels before they eat breakfast, before meals, approximately two hours after meals, and before going to bed at night.