Type 1 Diabetes: Test And Diagnosis

What is type 1 diabetes?

Type 1 diabetes is an autoimmune disease in which the body does not produce enough insulin. This is caused by autoantibodies that attack the pancreas' beta cells, which synthesize insulin. Insulin is essential for transporting glucose (sugar) from the blood into cells for energy and storage.

When insufficient insulin is produced, glucose accumulates in the blood, resulting in high blood sugar levels.

High blood sugar levels — hyperglycemia — can adversely affect the body, such as damage to blood vessels and an increased risk of heart disease.

Type 1 diabetes is not caused by being overweight or maintaining an unhealthy lifestyle. It has a genetic link, so people with a family history of type 1 diabetes are at an increased risk of developing the condition. However, not all people with a genetic predisposition develop type 1 diabetes.

Who should be tested for type 1 diabetes?

Some common symptoms are potential signs of type 1 diabetes. Ask your doctor for a diabetes test if you experience any of the following:

• Increased or persistent thirst

• Frequent urination

• Nausea and vomiting

• Blurred vision

• Fatigue

• Numbness in hands and feet

• Unexplained weight loss

• Increased hunger

• Headaches

Risk factors

Some risk factors make you more susceptible to developing type 1 diabetes. Get tested if the following risk factors apply to you.

Family history

If you have a family history of type 1 diabetes, you will likely develop this condition. However, not all people with a family history of diabetes will develop symptoms. Family history is the most critical risk factor.

Age

Type 1 diabetes most often develops in children, teenagers, and young adults. Because of this, type 1 diabetes is also sometimes called juvenile diabetes. However, it can develop at any age.

If you or your child are experiencing symptoms of diabetes, visit your doctor, especially if you have a known family history.

Autoimmune conditions

Some other autoimmune conditions increase your chances of developing type 1 diabetes. These include:

• Pernicious anemia

• Grave’s disease

• Multiple sclerosis

Viral infection

Certain viral infections are associated with the onset of type 1 diabetes, including:

• Mumps

• Rotavirus

• Enteroviruses (e.g., coxsackievirus)

• Cytomegalovirus

If you experience one of these viral infections, particularly if you have a family history of type 1 diabetes, you are at a higher risk of developing the condition.

What are the standard tests for type 1 diabetes?

Glycated hemoglobin (HbA1c) test

The glycated hemoglobin (HbA1c) test, also called an A1C test, tests the amount of glucose in red blood cells. Glucose (sugar) binds to a protein on red blood cells called hemoglobin, which carries oxygen around the body.

By measuring the percentage of hemoglobin with glucose bound to it (glycated hemoglobin), the level of blood sugar can be calculated:

• Under 5.7% glycated hemoglobin: this is a normal amount of sugar in the blood

• Between 5.7% and 6.4% glycated hemoglobin: this suggests prediabetes

• Over 6.5% glycated hemoglobin: this is indicative of diabetes

Glycated hemoglobin tests do not identify the type of diabetes you may have; they simply indicate whether you may or may not have diabetes. Further testing is required to determine if you have type 1 diabetes.

Oral glucose tolerance test

Oral glucose tolerance tests involve drinking a liquid containing a high concentration of glucose and monitoring the levels of glucose in the blood. You must fast for at least eight hours before taking an oral glucose test. Blood is taken before the solution is consumed, then every hour for one to two hours afterward.

If your blood glucose levels have not reduced after two hours and your blood sugar level is 200 mg/dL or more, it indicates diabetes. However, like HbA1c tests, oral glucose tolerance tests do not distinguish between type 1 and type 2 diabetes.

Fasting blood glucose test

A fasting blood glucose test is a blood test taken when fasting. This means you cannot eat or drink anything except water before your blood test. The best time to take a fasting blood glucose test is in the morning after fasting overnight.

A fasting blood glucose test examines the levels of sugar in the blood. If your blood glucose levels are over 126 mg/dL when fasting, you have diabetes. Like oral glucose and HbA1c tests, a fasting blood sugar test does not distinguish between type 1 and type 2 diabetes.

Random blood glucose test

A random blood glucose test is the same as a fasted blood glucose test, except you can eat before your blood test. Your blood sugar levels are expected to be higher than when you have fasted.

However, if these levels are too high, you may have diabetes. Blood sugar levels of 200 mg/dL or higher indicate diabetes, either type 1 or 2.

Tests specific for type 1 diabetes

Zinc transporter 8

Zinc transporter 8 (ZnT8) is a protein essential for insulin synthesis. ZnT8 autoantibodies attack the ZnT8 protein and destroy it, reducing the body's production of insulin.

ZnT8 autoantibodies may be present in the blood of people with type 1 diabetes. However, they will not be present in people with type 2 diabetes or those who do not have diabetes.

Insulin autoantibodies

Similar to the Zinc transporter 8 test, a test for insulin autoantibodies can determine whether you have type 1 diabetes. Insulin autoantibodies are present in the blood of people with type 1 diabetes exclusively.

Insulin autoantibodies attack the insulin produced by the pancreas. This causes a reduction in the amount of insulin available to move sugar from the blood to the cells throughout the body, raising blood sugar levels.

C-peptide

This test measures the amount of c-peptide in the blood or urine. The amount of c-peptide in the blood or urine usually mimics the amount of insulin produced in the body.

 If your blood or urine has low levels of c-peptides, it may indicate your body is not producing sufficient amounts of insulin. If this is the case, you may have type 1 diabetes.

Islet cell cytoplasmic autoantibodies

Islet cell cytoplasmic autoantibodies attack a cluster of cells in the pancreas called the islet cells. These cells are responsible for producing insulin. If islet cell autoantibodies attack these cells, sufficient insulin will not be made, causing high blood sugar levels.

These antibodies are present in approximately 80% of patients with type 1 diabetes and are not present in type 2 diabetes. Testing for islet cell cytoplasmic autoantibodies is usually done through a blood test.

Glutamic acid decarboxylase (GAD) antibodies

Glutamic acid decarboxylase (GAD) is an enzyme in pancreatic islet beta cells. GAD autoantibodies attack GAD and their presence indicate type 1 diabetes.

To test for GAD autoantibodies, a blood sample is taken and tested. GAD autoantibodies are found in approximately 75% of patients with type 1 diabetes.

Insulinoma antigen-2 (IA2) antibodies

Similar to the insulin, islet cell, and GAD autoantibodies tests, the presence of IA2 antibodies in a blood sample indicates type 1 diabetes.

Tips on how to prepare for type 1 diabetes testing

The prospect of a diabetes test can be daunting and potentially confusing. Here are some tips to help you prepare for a type 1 diabetes test.

Find out what tests you will be having

The most important thing to know before a diabetes test is what kinds of tests the doctor will run. This gives you time to research the different tests and understand what you must do.

Finding out what kinds of tests you will undergo also allows you some time in advance to think of any questions you might want to ask your doctor before the testing starts.

Find out what is required of you

Make sure you know what you need to do before the diabetes test. Some tests require you to fast for at least eight hours beforehand, while others can be done at any time of the day.

Ensuring you know what you need to do will help the tests go smoothly and prevent delays.

Ask a friend to come along

Going to the doctor for health tests can make some people apprehensive. Whether it is because of the test itself (such as a fear of needles) or possible results, it is normal to be a bit anxious.

If you are nervous about diabetes testing, ask a friend or family member to accompany you.

If no one can come with you, mention to your doctor that you would like a support person, and often a receptionist or nurse will come and sit with you.

What to do if you're diagnosed with type 1 diabetes

If you are diagnosed with type 1 diabetes, you must have regular check-ups and tests with your doctor to ensure you are managing your condition well.

There are also some educational and support services for diabetes management. If you want to join one of these, your doctor can refer you to a local one.

A1C test

As well as being used to diagnose diabetes, A1C tests can be used throughout diabetes management to ensure your blood glucose levels remain well controlled.

By measuring the percentage of red blood cells with glucose bound to them, A1C tests can determine whether your diabetes is being effectively managed or if you may require additional treatment.

Periodic blood and urine samples

Regular blood and urine tests can help ensure the proper management of type 1 diabetes. Urine samples can be tested for ketones, bacteria, and proteins.

Ketones are present in the urine when the body burns fat for fuel instead of sugar. This can occur in type 1 diabetes when sugars are not transported to the cells from the blood. If this happens, you may be at risk of developing diabetic ketoacidosis, a severe complication of diabetes.

Bacteria is an indicator of a urinary tract infection (UTI). Patients with type 1 diabetes are at an increased risk of developing UTIs.

High levels of protein in urine are an indicator of kidney damage. A common complication of type 1 diabetes is diabetic nephropathy — kidney damage resulting from diabetes. The kidneys are essential for filtering waste from the blood.

Diabetes can cause damage to the blood vessels in the kidney, resulting in kidney damage and high blood pressure.

Regular blood tests are essential for ensuring your blood glucose levels are normal, as well as managing cholesterol levels. Diabetes alone increases the risk of heart disease. LDL — a type of cholesterol — can clog up blood vessels if too much is present in the body, further increasing the risk of heart disease.

Blood pressure checks

Typically, the blood pressure of a person with diabetes should be below 140/90mm Hg, but this may vary from person to person.

As diabetes increases the risk of heart disease, it is essential to regularly check your blood pressure to keep this risk under control.

Regular feet and eye checks

One common complication of diabetes is foot problems. This can result from diabetic neuropathy — damage to nerves due to diabetes. This nerve damage can result in tingling and a loss of feeling in the feet, leading to cuts and scrapes potentially going unnoticed.

If cuts to the feet are not noticed and taken care of, they may become infected. This risk is increased by the reduced blood flow to the feet, also caused by diabetes. The reduction of blood flow makes it harder for wounds to heal.

Severe infection may lead to a condition called gangrene, which, if not improved by treatment, may result in amputation of part or all of the injured foot.

Additionally, diabetes can affect eye health. Long periods of high blood glucose levels damage the blood vessels in the eyes. This may cause high blood pressure or scarring in the eyes.

In the long term, four conditions may affect your vision due to blood vessel issues:

• Diabetic retinopathy 

• Diabetic macular edema 

• Glaucoma 

• Cataracts 

To reduce the risk of developing severe foot or eye problems, have annual checkups with a foot and eye specialists.

How is type 1 diabetes treated?

Insulin therapy

Type 1 diabetes is primarily treated by insulin therapy. Insulin can be injected via an insulin pen or syringe or administered constantly through an insulin pump.

Alternatively, insulin may be obtained through an artificial pancreas. This device mimics a human pancreas, monitoring blood glucose levels and delivering insulin doses as needed.

Carbohydrate counting

Counting carbohydrates is important in type 1 diabetes management. Carbohydrates turn into glucose when consumed and affect blood glucose levels more than fats and proteins.

Counting your carbohydrate intake will make determining how much insulin to inject easier. Visit a dietitian or diabetes support services to learn how to count carbohydrates.

Frequent blood sugar monitoring

Monitoring your blood sugar levels frequently will reduce the risk of complications and help assess the success of diabetes treatment.

If your blood sugar levels remain high, this may indicate your current treatment plan is ineffective, and further steps will be needed to avoid complications and worsening of your condition.

Eating healthy food

Eating healthy food will help you maintain a healthy weight and prevent complications of type 1 diabetes from developing. If you're unsure where to start, diabetes support services can help you create a meal plan.

Diabetes meal plans often contain a mix of:

• Vegetables

• Fruits

• Whole grains

• Protein

• Nonfat or low-fat dairy products

• Heart-healthy fats such as nuts, salmon, and olive oil

If you have type 1 diabetes, you should limit or altogether avoid:

• Fried foods

• Foods high in salt

• Foods high in sugar such as baked goods, ice cream, and candies

• Beverages high in sugar, such as regular soda and juice

Regular exercise

Regular exercise lowers blood pressure and blood glucose levels. It also improves blood flow and mood.

Keeping fit is beneficial for everyone, especially for people with diabetes, as they are at an increased risk of developing heart conditions and other complications.

Approximately 30 minutes of moderate exercise five days a week is considered beneficial to type 1 diabetes management. Popular activities for diabetes management include:

• Walking

• Cycling

• Dancing

• Swimming

If you are concerned about what exercises you can do or the intensity of these exercises, chat with your doctor.

How can type 1 diabetes be prevented?

Unfortunately, type 1 diabetes cannot be prevented. However, researchers are looking at three possible stages of type 1 diabetes prevention: primary, secondary, and tertiary prevention.

Primary prevention

Primary prevention is for those with a high risk of developing type 1 diabetes but who have not yet developed autoimmunity, such as young children with a family history of type 1 diabetes.

One study¹ is determining whether administering oral insulin to high-risk infants daily will prevent autoimmunity from developing.

Another form of primary prevention being studied is vaccination. This includes vaccinating against the viral infections linked² to the onset of type 1 diabetes and a vaccine that may induce immune tolerance in those at a high risk of developing type 1 diabetes.

Secondary prevention

Secondary prevention would be offered to patients who have already developed some autoantibodies to prevent the onset of clinical diabetes. Current prevention methods being studied include continuous glucose monitoring and oral glucose tolerance testing.³

Tertiary prevention

Tertiary prevention would occur for patients who have type 1 diabetes and is to prevent complications from occurring and to preserve beta cell mass.

Vitamin D may slow the progression of type 1 diabetes, but there is not enough evidence to be certain.

When to visit a doctor

Consider visiting a doctor to discuss getting tested for type 1 diabetes if:

• You are experiencing potential symptoms of the condition

• You have a family history of the condition, whether or not you have symptoms

Getting tested as soon as possible ensures the appropriate treatment can be started if required.

If you have been diagnosed with type 1 diabetes and are struggling to manage your symptoms or feel they are worsening, visit your doctor for advice. They may need to adjust your treatment or refer you to additional support services.

The lowdown

Type 1 diabetes can be diagnosed using simple blood tests. If you are concerned about the possibility of type 1 diabetes, visit your doctor to discuss having tests done to ensure you receive treatment as soon as possible.

The earlier you are diagnosed, the more likely you can avoid complications.