Blood sugar test: what is it?

Recognising Diabetes Week (12th-18th June 2023)

As a charity, our heritage is steeped in offering support and education for those living with and managing variants of diabetes. We’re recognising Diabetes Week 2023, by offering a range of additional blogs and e-bulletins around this important subject.

A blood sugar test can be used to determine the amount of glucose in the blood. Glucose is a simple sugar (like fructose) and is sourced through the digestion of food into a source of energy or fuel for the body to operate and stay alive. Furthermore, a blood sugar test may be used to diagnose diabetes or to help those with diabetes check their blood sugar and insulin levels.

What is a blood sugar test?

A blood sugar test is a procedure that measures the amount of sugar, or glucose, in your blood. A doctor may order this test to help diagnose diabetes. People with type 1 and type 2 diabetes also use this test to manage their condition.

Type 1 diabetes occurs when the cells in the body responsible for producing the hormone insulin are destroyed. Type 2 diabetes occurs when your body becomes resistant to insulin and no longer uses it effectively. Both types can result in high blood sugar if they’re not managed well.

Blood sugar tests provide instant results and let you know the following:

·       if your blood sugar levels are high or low

·       if your diet or exercise routine needs to change

·       how your diabetes treatment is working

·       if your overall treatment goals for diabetes are manageable

If you have not been diagnosed with diabetes, a doctor may also recommend a blood sugar test as part of a routine check-up. They may also be looking to see if you have diabetes or prediabetes, a condition where your blood sugar levels are higher than typical.

People may need to be tested if they have symptoms of diabetes or if they have certain risk factors.

Risk factors for diabetes

You may be more likely to get type 1 diabetes if you:

·       are a teenager or younger (this does not take into account the growing number of LADA - Latent autoimmune diabetes in adults -patients)

·       have a family member with the condition

·       have certain genes that give you a genetic predisposition

Your risk for type 2 diabetes may increase if you:

·       are age 35 years or older (although this is no longer strictly the case)

·       are overweight

·       are not physically active

·       have a family history of diabetes

·       have a history of insulin resistance or have prediabetes

·       have a history of gestational diabetes or gave birth to a baby who weighed over 9 pounds

·       have high blood pressure, high triglycerides, or high cholesterol (contributors of metabolic syndrome conditions)

·       have a history of stroke or hypertension

Research has shown that type 2 diabetes occurs more often in adults of certain ethnic backgrounds or ancestry. They may also be more likely to experience decreased quality of care and increased barriers to prevention and self-management support due to healthcare disparities. Checking your blood sugar levels can be done at home or in a GP’s office.

What does a blood sugar test do?

Your GP may recommend a blood sugar test to see if you have diabetes or prediabetes. The test will measure the amount of glucose in your blood. Your body takes carbohydrates found in foods like grains and fruits and converts them into glucose. Glucose, a sugar, is one of the body’s main sources of energy. 

For people with diabetes, a home test helps monitor blood sugar levels more consistently. Regularly taking a blood sugar test can help determine your blood sugar level to see if you need to adjust your diet, exercise, or diabetes medications. 

Low blood sugar (hypoglycaemia) can lead to severe hypos which can take the form of seizures or a coma if left untreated. 

High blood sugar (hyperglycaemia) can lead to diabetic ketoacidosis, a life-threatening condition that’s often a concern for those with type 1 diabetes. Hyperglycaemia over a long period can increase your risk of neuropathy (nerve damage), along heart, kidney and eye diseases.

Diabetic ketoacidosis vs. ketosis

Diabetic ketoacidosis happens when your blood sugar is very high and ketones reach dangerous levels in your body. Ketosis occurs when the body uses fat for energy. This can happen as a result of an extremely low carbohydrate diet or from fasting.

What are the risks and side effects of a blood sugar test?

A blood sugar test has low to no risks or side effects. You may feel soreness, swelling, and bruising at the puncture site, especially if you’re drawing blood from a vein. This should go away within a day. 

Types of blood sugar tests

You can take a blood sugar test two ways. People who are monitoring or managing their diabetes may use a glucometer for daily testing. This method involves pricking the skin (usually a finger) with a lancet to draw a blood sample, applying the blood on a test strip, and inserting it into the monitor. 

The second method involves a healthcare professional drawing a blood sample and sending it to a lab to be evaluated. Blood samples are generally used to screen for diabetes. A doctor will typically order a HbA1c test, which measures your blood sugar levels, as an average, over the last three months. The results will show if you have prediabetes or diabetes. In people already diagnosed with diabetes, this test can monitor how well their diabetes is managed.

When to test blood sugar

When and how often you should test your blood sugar depends on the type of diabetes you have and your treatment. 

Type 1 diabetes

According to research, if you’re managing type 1 diabetes with multiple-dose insulin or an insulin pump, you’ll want to monitor your blood sugar:

·       before eating a meal or snack

·       2–3 hours after eating

·       before sleeping

·       if you feel any symptoms of low or high blood sugar

High blood sugar

It is recommended for you to check your blood sugar levels if you have diabetes and feel increasing thirst and the urge to urinate. These could be symptoms of high blood sugar. This may be a sign that you may need to modify your treatment plan. If your diabetes is managed well but you still have symptoms, it may mean you’re getting sick or that you’re under stress.

Exercising, better sleep hygiene, improved stress management, as well as managing your carbohydrate intake may help with lowering your blood sugar levels. If these changes don’t work, you may need to meet with a doctor to decide how to get your blood sugar levels back into target range.

Low blood sugar

According to the ADA, you should check your blood sugar levels if you feel any of the following symptoms:

·       shaky

·       sweaty or chilly

·       irritated or impatient

·       confused

·       lightheaded or dizzy

·       hungry and nauseous

·       sleepy

·       tingly or numb in the lips or tongue

·       weak

·       angry, stubborn, or sad

Severe symptoms like delirium, seizures, or unconsciousness can be symptoms of low blood sugar or insulin shock. You can also have low blood sugar and show no symptoms. This is called hypoglycaemia unawareness. If you have a history of hypoglycaemia unawareness, you may need to test your blood sugar more often.

Home tests

You can take blood sugar tests at home with a glucometer or with a blood test. The exact steps for finger sticks or glucose meter tests vary depending on the type and brand of test. Your home kit will provide instructions on use.

Typically, the procedure involves pricking your finger with a lancet and putting the blood on a testing strip. The strip is then inserted into a glucometer. Your results usually show on the screen in 10 to 20 seconds.

Continuous glucose monitoring (CGM)

You can also wear a device for continuous glucose monitoring (CGM). A glucose sensor is inserted under your skin and continuously reads the sugar in your body tissue. It alerts you whenever your blood sugar is too low or too high. The sensor can last several days to a week before you need to replace it. You’ll still have to check your blood sugar with a meter to calibrate your CGM every several days to 2 weeks.

What do the results of the blood sugar test mean?

Depending on your condition and the timing of your test, your blood sugar levels should be in certain target ranges. A doctor may provide a more specific target range for your blood sugar levels depending on the following factors:

  • personal history

  • how long you’ve had diabetes

  • presence of diabetes complications

  • age

  • pregnancy

  • overall health

Tracking your blood sugar levels is one way to better manage your diabetes. You may find it helpful to log your results in a journal or app. Trends like continuously having levels that are too high or too low may mean working with your healthcare professional to adjust your treatment for better results.

Extracts taken from MaryAnn De Pietro, CRT from https://www.healthline.com

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