- How to measure blood glucose
- 1. Capillary glycemia
- 2. Fasting blood glucose
- 3. Glycated hemoglobin
- 4. Glycemic curve
- 5. Postmeal plasma glucose
- 6. Blood glucose sensor in the arm
- What is it for
- What are the reference values
- 1. Low blood glucose
- 2. High blood glucose
Glycemia is the term that refers to the amount of glucose, better known as sugar, in the blood that comes from eating foods that contain carbohydrates, such as cake, pasta and bread, for example. The concentration of glucose in the blood is controlled by two hormones, insulin which is responsible for the decrease of sugar in the bloodstream and the glucagon which has the function of increasing glucose levels.
There are several ways to measure blood glucose levels through blood tests, such as fasting blood glucose and glycated hemoglobin, or by means of easy-to-use blood glucose meters and devices that the person can use.
The blood glucose reference values should ideally be between 70 to 100 mg / dL when fasting and when it is below this value it indicates hypoglycemia, which causes symptoms such as drowsiness, dizziness and even fainting. Hyperglycemia, on the other hand, is when blood glucose is above 100 mg / dL while fasting and may indicate type 1 or type 2 diabetes, which if not controlled can cause complications, such as vision problems and diabetic foot. Know other symptoms of diabetes.
How to measure blood glucose
Blood glucose refers to the concentration of glucose in the blood and can be measured in several ways, such as:
1. Capillary glycemia
Capillary blood glucose is an exam that is carried out by the prick of a finger and then the drop of blood is analyzed on a tape connected to a device called a glucometer. Currently, there are several models of different brands of glucometer, it is found for sale in pharmacies and can be performed by anyone, as long as it is previously oriented.
This type of test allows people who have diabetes to have greater control over blood glucose levels, preventing episodes of hypoglycemia due to the use of insulins, helping to understand how food, stress, emotions and exercise alter blood sugar levels. blood glucose and also helps to set the correct insulin dose to be administered. See how to measure capillary blood glucose.
2. Fasting blood glucose
Fasting blood glucose is a blood test performed to check blood glucose levels and should be done after a period without eating or drinking, except water, for at least 8 hours or as directed by the doctor.
This test helps the general practitioner or endocrinologist to diagnose diabetes, however, more than one sample should be collected and further tests, such as glycated hemoglobin, may be recommended for the doctor to close the diagnosis of diabetes. Fasting glycemia can also be performed for the doctor to assess whether treatment for diabetes is being effective or to monitor other health problems that alter blood glucose levels.
3. Glycated hemoglobin
Glycated hemoglobin, or HbA1c, is a blood test performed to assess the amount of glucose bound to hemoglobin, a component of red blood cells, and refers to the blood glucose history over 120 days, as it is this period of life of the red blood cell and the time it is exposed to sugar, forming glycated hemoglobin, and this test is the most used method to diagnose diabetes.
The normal reference values for glycated hemoglobin should be less than 5.7%, however, in some cases, the result of glycated hemoglobin may be altered due to some factors, such as anemias, drug use and blood diseases, for example. this before the exam is carried out the doctor will analyze the person's health history.
4. Glycemic curve
The glycemic curve, also known as a glucose tolerance test, consists of a blood test in which fasting glycemia is verified and 2 hours after ingesting 75 g of glucose through the mouth. In the 3 days before the exam, the person needs to eat a diet rich in carbohydrates, such as breads and cakes, for example, and then must fast for 12 hours.
In addition, it is important that before taking the exam, the person has not had coffee and has not smoked for a period of at least 24 hours. After the first blood sample is collected, the person will ingest the glucose and then rest for 2 hours to collect blood again. After the exam, the result takes between 2 to 3 days to be ready, depending on the laboratory and the normal values should be below 100 mg / dL on an empty stomach and 140 mg / dL after the ingestion of 75g of glucose. Better understand the result of the glycemic curve.
5. Postmeal plasma glucose
Postprandial blood glucose is an exam to identify blood glucose levels between 1 and 2 hours after a person has eaten a meal and is used to assess peaks of hyperglycemia, associated with cardiovascular risk or any problem with insulin release. This type of test is generally recommended by a general practitioner or endocrinologist to complement the fasting blood glucose test and normal values should be below 140 mg / dL.
6. Blood glucose sensor in the arm
Currently, there is a sensor to check the blood glucose that is implanted in a person's arm and allows the verification of blood glucose levels without the need to perform a finger prick. This sensor is a round device with a very fine needle that is inserted in the back of the arm, does not cause pain and does not cause discomfort, being used even for diabetic children, as it reduces the discomfort of having to pierce the finger.
In this case, to measure blood glucose, just bring the cell phone, or the brand specific device, to the arm sensor and then the scan will be done and the result will appear on the cell phone screen. The sensor must be changed every 14 days, however it is not necessary to perform any type of calibration, different from the common capillary blood glucose device.
What is it for
Blood glucose is indicated by a general practitioner or endocrinologist to check blood glucose levels and through this it is possible to detect certain diseases and conditions, such as:
- Type 1 diabetes; Type 2 diabetes; Gestational diabetes; Insulin resistance; Thyroid changes; Pancreatic diseases; Hormonal problems.
Glycemic control can also complement the diagnosis of Dumping syndrome, for example, which is a condition in which food passes quickly from the stomach to the intestine, leading to the appearance of hypoglycemia and causing symptoms such as dizziness, nausea and tremors. Learn more about Dumping syndrome.
Often, this type of analysis is done as a hospital routine in people who are hospitalized and who receive serum with glucose or use medications in their veins that can cause blood glucose levels to drop significantly or rise rapidly.
What are the reference values
The tests to check capillary blood glucose are diverse and may vary according to the laboratory and tests used, however the results should generally have values as shown in the table below:
|
In fasting |
After 2 hours of meals |
Any time of day |
|
| Normal blood glucose | Less than 100 mg / dL | Less than 140 mg / dL | Less than 100 mg / dL |
| Altered blood glucose | Between 100 mg / dL to 126 mg / dL | Between 140 mg / dL to 200 mg / dL | Unable to set |
| Diabetes | Greater than 126 mg / dL | Greater than 200 mg / dL | Greater than 200 mg / dL with symptoms |
After checking the results of the test, the doctor will perform an analysis of the symptoms presented by a person and may recommend other tests to check the possible causes of low or high blood glucose.
1. Low blood glucose
Low blood glucose, also called hypoglycemia, is the decrease in blood glucose levels, identified by values below 70 mg / dL. The symptoms of this condition can be dizziness, cold sweat, nausea, which can lead to fainting, mental confusion and coma if it is not reversed in time, which can be caused by the use of medications or the use of insulin in very high doses. See more what can cause hypoglycemia.
What to do: Hypoglycemia should be treated quickly, so if a person has milder symptoms, such as dizziness, you should offer a juice box or something sweet right away. In the most serious cases, in which mental confusion and fainting occur, it is necessary to call the SAMU ambulance or take the person to an emergency, and offer sugar only if the person is conscious.
2. High blood glucose
High blood glucose, better known as hyperglycemia, occurs when blood sugar levels are too high because of eating very sweet, carbohydrate-based foods, which can lead to diabetes. This change does not normally cause symptoms, however, in cases where blood glucose is too high and for a long time, dry mouth, headache, drowsiness and frequent urination may appear. Check why hyperglycemia happens.
What to do: In cases where diabetes is already diagnosed, the doctor usually recommends the use of hypoglycemic drugs, such as metformin, and injectable insulin. In addition, in some cases, hyperglycemia can be reversed through dietary changes, reducing the consumption of foods rich in sugar and pasta and through regular physical activities. See in the video below which exercises are most recommended for those with diabetes:
