How Do You Get Diagnosed With Type 2 Diabetes?

Type 2 diabetes is a condition that develops gradually, often with subtle symptoms that can be easily overlooked.

The main symptoms include:

1. Polyuria: Frequent urination
2. Polydipsia: Increased thirst
3. Polyphagia: Increased hunger

At a glance, these symptoms may seem insignificant or attributable to other causes, leading many people to delay seeking medical advice.

However, timely diagnosis is crucial for effective management and prevention of complications.

So, how exactly do you get diagnosed with type 2 diabetes? Let’s explore the diagnostic process in detail.

The Importance of Blood Tests

To confirm a diagnosis of type 2 diabetes, a doctor will order blood tests to measure your blood sugar levels.

Common tests include:

1. Fasting Blood Glucose Test
2. Oral Glucose Tolerance Test (OGTT)
3. Hemoglobin A1c (HbA1c) Test

Another test that your doctor may not test but is incredibly important is testing insulin levels, as this can provide valuable insights, particularly in detecting insulin resistance at an earlier stage.

Fasting Blood Sugar Test

First your doctor will be checking to see if your blood sugar level (aka blood glucose level) is in the normal range.

The fasting blood sugar test is one of the most common tests for diagnosing diabetes. It requires fasting for at least 8 hours (overnight) before having your blood drawn. Tip: Go first thing in the morning.

This test measures the glucose levels in your bloodstream after fasting and is a reliable indicator of your metabolic health.

Here are the diagnostic thresholds:

• Normal: Less than 100 mg/dL (less than 5.6 mmol/L)
  • NOTE: In Canada, UK and Australia, normal is less than 6.1 mmol/L (yes, this is confusing as it should be the same all over the world, but it isn’t)
• Prediabetes: 100–125 mg/dL (5.6–6.9 mmol/L)
  • NOTE: In Canada, UK and Australia, you will be diagnosed with prediabetes if your fasting levels are 6.1-6.9 mmol/L
• Diabetes: 126 mg/dL (7.0 mmol/L) or higher

So, if your fasting blood glucose is 99 mg/dL (6.0 mmol/L), it falls within the normal range. If it’s 100 mg/dL (6.1 mmol/L), it’s considered prediabetes.

If it’s 126 mg/dL (7.0 mmol/L) or higher, you will be diagnosed with type 2 diabetes.

Oral Glucose Tolerance Test (OGTT)

The OGTT is used less frequently but is particularly useful for diagnosing impaired glucose tolerance (IGT)—a precursor to type 2 diabetes.

This test involves fasting for at least 10 hours, followed by consuming a 75-gram glucose solution. Blood samples are taken at fasting, and then at 1 and 2 hours after drinking the solution.

Diagnostic thresholds for the OGTT are:

• Normal: 2-hour glucose <140 mg/dL (<7.8 mmol/L)
• Impaired Glucose Tolerance: 140–199 mg/dL (7.8–11.0 mmol/L)
• Diabetes: ≥200 mg/dL (≥11.1 mmol/L)

While the outcomes align with the fasting blood glucose test, the OGTT provides additional clarity, especially when blood sugar levels fall into borderline ranges.

Hemoglobin A1c (HbA1c) Test

The A1c test reflects your average blood sugar levels over the past 2–3 months by measuring the percentage of glucose attached to hemoglobin in your red blood cells.

In the US:

• Normal: <5.7%
• Prediabetes: 5.7–6.4%
• Diabetes: ≥6.5%

In Canada, UK and Australia:

• Normal: <6.0% (<42 mmol/mol)
• Prediabetes: 6.0–6.4% (42 to 47 mmol/mol)
• Diabetes: ≥6.5% (≥48 mmol/mol)

This test is particularly useful because it isn’t influenced by day-to-day fluctuations in blood sugar due to recent meals.

Once diagnosed with diabetes, monitoring A1c levels every 3–6 months helps track long-term blood sugar control.

Why Insulin Testing Matters

While blood sugar tests are standard for diagnosing diabetes, testing fasting insulin levels can provide critical insights into insulin resistance—an underlying cause of type 2 diabetes and prediabetes.

Many people with insulin resistance maintain normal blood sugar levels in the early stages, masking the problem until significant damage has occurred.

Fasting Insulin Test Indicators

• 10 mIU/L or lower: Ideal, good insulin sensitivity
• 11–14 mIU/L: Mild insulin resistance
• 14 mIU/L: Moderate insulin resistance
• Over 20 mIU/L: Abnormally high insulin levels, strong insulin resistance

If your fasting insulin levels are elevated, it’s a strong indication of insulin resistance, even if your blood sugar levels appear normal.

Why Ask for an Insulin Test?

Early detection of insulin resistance can help prevent type 2 diabetes and its complications.

Don’t hesitate to request this test from your doctor, especially if you have risk factors such as a family history of diabetes, obesity, high stress levels or a sedentary lifestyle.

What is Prediabetes and Why Does It Matter?

Prediabetes is a condition where blood sugar levels are elevated but not high enough for a diabetes diagnosis. It’s a warning sign that your body is struggling to regulate blood sugar effectively.

Prediabetes is a critical window of opportunity. Addressing it early through diet, exercise and lifestyle changes can prevent progression to type 2 diabetes.

Unfortunately, many people underestimate the seriousness of prediabetes, even though much of the damage to blood vessels and organs begins at this stage.

Risk Factors for Type 2 Diabetes

Understanding your risk factors can help you stay proactive about your health.

Common risk factors include:

• Family History: A parent or sibling with type 2 diabetes.
• Age: Risk increases after age 45.
• Weight: Being overweight or obese, particularly with abdominal fat.
• Lifestyle: Sedentary behavior and poor diet.
• Medical Conditions: High blood pressure, high cholesterol, or a history of gestational diabetes.

If you have one or more of these risk factors, regular blood sugar testing is essential.

How Often Should You Get Tested?

If you’re over 45, it is recommended to get blood sugar screening every 3 years for individuals over 45.

If you’re younger but have risk factors, consider more frequent testing.

For those already diagnosed with prediabetes or diabetes, routine monitoring of blood sugar, A1c, and insulin levels (if applicable) can help guide nutritional treatment and lifestyle decisions.