Type 2 diabetes (T2D) is a condition where the body cannot use or process insulin to manage blood sugar levels successfully. Various tests can measure blood sugar levels to help diagnose the condition.

T2D is the most common type of diabetes. It typically occurs when the body no longer responds correctly to the hormone insulin. This hormone is responsible for regulating the movement of blood glucose, or sugar, into cells, which use it as energy. This is known as insulin resistance. After some time, the pancreas begins to make less and less insulin.

This causes blood sugars to rise, which can cause a variety of symptoms and complications. To diagnose T2D, a doctor will typically administer a blood test to assess a person’s blood sugar level. If the blood test results are above a certain threshold, it may indicate that they have T2D.

In this article, we will discuss the diagnostic criteria for T2D and the risk factors and prevention strategies for the condition.

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Typically, to receive a diagnosis of T2D, a person will initially present with symptoms, such as increased thirst, frequent urination, and fatigue. A doctor will then suggest different tests to measure a person’s blood sugar levels. A high blood sugar reading may indicate T2D. However, not all individuals will show symptoms. They may receive a diagnosis from routine tests.

According to the National Institute of Diabetes and Digestive and Kidney Disorders (NIDDK), there are several tests a medical professional may use to diagnose T2D. These include the below.

Fasting plasma glucose

This test looks at a person’s blood sugar level at a singular point. For reliable results, a doctor may administer this blood test after someone has fasted for a minimum period of at least 8 hours.

In the United States, a doctor will report the results of the fasting plasma sugar test in milligrams per deciliter (mg/dL). The World Health Organisation (WHO) suggests that if results are between 100 and 125 mg/dL, a doctor may recommend certain lifestyle changes and monitoring sugar levels. If a person has this result, healthcare professionals may give them a diagnosis of prediabetes.

If an individual’s fasting blood sugar is 126 mg/dL or higher on two separate tests, a doctor will diagnose them with diabetes.

A1C test

The A1C test is a blood test that provides a person’s average levels of blood sugar over the last 3 months. Individuals can eat and drink before this test.

A doctor will report the results of this test as a percentage. According to the Centers for Disease Control and Prevention (CDC), an A1C result of 5.7% to 6.4% is indicative of prediabetes, while an A1C result of 6.5% or higher suggests diabetes.

Before a doctor recommends an A1C test, they will consider factors that may render the screening inaccurate. For example, certain types of anemia and being in the second or third trimester of pregnancy may affect the accuracy of the test.

Other names for this test are:

  • glycated hemoglobin
  • glycosylated hemoglobin
  • hemoglobin A1C
  • HbA1c test

Oral glucose tolerance test

This test measures the body’s response to glucose, or blood sugar. A doctor will ask a person to fast for at least 8 hours before the test. They will then take a blood test to get a baseline measurement of someone’s blood sugar levels. The individual will then drink a dose of glucose and undergo a second blood test after 2 hours.

A fasting blood sugar level greater than 126mg/dL and a 2-hour level greater than 200 mg/dL would suggest T2D.

Random plasma glucose test

If someone shows symptoms of T2D, a doctor may use a random plasma glucose test. This test does not require a period of fasting. Instead, a doctor can conduct this test at any time. A result greater than or equal to 200 mg/dL would indicate type 2 diabetes.

There are some factors that may put a person at a higher risk of developing T2D. These include:

  • living with prediabetes
  • being overweight or living with obesity
  • being aged 45 years or over
  • having a close relative with T2D
  • taking part in physical activity less than three times a week
  • having a previous diagnosis of gestational diabetes or birthing a baby weighing over 9 pounds
  • having African American, Hispanic or Latino, American Indian, Alaska Native Person, Pacific Islander, or Asian American heritage
  • having nonalcoholic fatty liver disease

There are several lifestyle changes a person can make to prevent or reduce their chances of developing T2D. These can include:

  • Increasing physical activity: It is advisable for a person to aim for at least 30 minutes of physical activity 5 days a week. If a person needs to get used to physical activity, they can start slow and build up toward a goal.
  • Maintaining a moderate weight: If a person has overweight or obesity, they can discuss ways of maintaining a moderate weight with a healthcare professional.
  • Regularly eating nutritious foods: A person may consider dietary changes, such as choosing foods with less fat and drinking water instead of sweetened drinks.

Type 2 diabetes is a health condition that may cause blood sugar levels to rise. Long periods of elevated blood sugars can result in health problems and complications.

Diagnosing type 2 diabetes typically involves a blood test to measure the amount of glucose in the blood.

Certain risk factors may put someone at greater risk of developing type 2 diabetes. However, certain lifestyle choices may help prevent or slow the progression of type 2 diabetes.