What not to eat before donating blood for sugar and cholesterol: how to prepare for analysis

To determine metabolic disorders, various diagnostic methods are used, the simplest and most informative of them is a biochemical blood test.

To diagnose diabetes, a blood test for sugar is performed. This test shows the baseline (basal) glucose level and is suitable for detecting the initial stages of diabetes, used to monitor treatment.

The level of cholesterol in the blood reflects the tendency to develop atherosclerosis, the presence of abnormalities in the functioning of the liver or kidneys, as well as the work of the endocrine glands – pancreas and thyroid.

Preparation for laboratory research

In the event that blood tests are scheduled, there are general rules on how to prepare for blood donation for both sugar and cholesterol.

A biochemical blood test should be taken from a vein on an empty stomach. This means that the last time before the analysis, you can eat 12 hours before. You can not drink tea, juice or coffee – this can also distort the results. On the day when blood is taken, only drinking water in normal quantities is allowed.

The day before the examination, preparation for delivery provides for the exclusion of alcohol. You can not eat fatty meat and fish, fried foods. It is recommended to reduce the consumption of eggs, fatty cottage cheese, fatty and spicy sauces. After a plentiful meal during a feast, at least two days should pass. Eaten on the day of the study, even a light breakfast, can completely distort the result.

Before donating blood, please note that you can not smoke for an hour.

If drug therapy has been prescribed or the patient is taking any medications on his own, then the date of the analysis should be agreed with the attending physician. It is impossible to donate blood while taking diuretics, hormones, antibiotics.

After diagnostic examinations – radiography, sigmoidoscopy or physiotherapy procedures, at least a day should pass.

On the day of the study, as a rule, intensive physical activity is not recommended, and the sauna cannot be visited the day before.

The question of how to properly take a blood test for cholesterol or examine blood for sugar in various phases of the menstrual cycle in women is not relevant for these types of tests. It is permissible to carry out diagnostics on any day.

For a correct assessment of the results during repeated studies, it is desirable to take them in the same laboratory.

Preparing and conducting a blood sugar test

A blood test for sugar is indicated to determine carbohydrate metabolism and detect diabetes.

In addition, the level of sugar can help in the diagnosis of diseases of the thyroid gland, adrenal glands, pituitary gland and liver.

To detect diabetes mellitus, such a study must be carried out when symptoms appear:

  • Increased thirst or hunger.
  • Copious and frequent urination, especially at night.
  • With sharp fluctuations in weight.
  • In case of frequently recurring infectious diseases, persistent thrush.
  • With the development of skin diseases that are difficult to treat.
  • Sudden or progressive visual impairment.
  • Skin itching and dryness of the skin.
  • Poor healing of skin lesions.

Before the analysis, stressful situations and excessive physical activity should be avoided. For the study, it does not matter where the blood is taken from – from a finger or from a vein, the indicators for both options will be the same.

The results obtained are normal in patients from 14 to 60 years old, in the norm from 4.6 to 6.4 mmol / l. This range refers to the study by the glucose oxidant method. With other methods, there may be deviations from these figures.

Elevated glucose levels occur with the following pathologies:

  1. For diseases like type 1 and type 2 diabetes.
  2. During physical exertion, strong emotional reactions, stress, smoking.
  3. With diseases of the thyroid gland.
  4. In case of impaired adrenal function.
  5. Diseases of the pancreas – pancreatitis in the acute and chronic stages.
  6. Chronic diseases of the liver.
  7. Impaired kidney function.
  8. With heart attacks and strokes of the brain.
  9. If the patient took diuretics, caffeine, estrogens or hormones before the analysis.

Low insulin levels may be due to:

  1. Tumors of the pancreas – adenoma, carcinoma, insulinoma .
  2. Hormonal pathologies – Addison’s disease, adrenogenital syndrome.
  3. Decreased thyroid function.
  4. Overdose of insulin or antidiabetic drugs.
  5. Cirrhosis and liver cancer.
  6. Tumors of the stomach.
  7. Prolonged fasting.
  8. Malabsorption in the intestine.
  9. Poisoning with arsenic, salicylates, alcohol.
  10. Heavy physical activity.
  11. Taking anabolics.

For the correct diagnosis of diabetes, only a single blood test for glucose is not suitable. Since this does not reflect the degree of change in carbohydrate metabolism.


Therefore, for procedures such as tests to detect diabetes, in addition, studies should be carried out – a glucose tolerance test, determination of the level of glycated hemoglobin.

Preparing for a cholesterol test and evaluating the results

Cholesterol in the body is found in the cell membrane, in the brain and nerve fibers. It is part of lipoproteins – a combination of protein and fats. According to their properties, they are divided into lipoproteins:

  • High density – good cholesterol, it cleanses the blood vessels.
  • Low density – a bad type of cholesterol, in the form of cholesterol plaques is deposited on the walls of blood vessels, atherosclerosis develops.
  • Very low density – the worst kind, it is an indicator of diabetes, severe pancreatitis, gallstone disease and hepatitis.

To prepare for the study, you need to eliminate all fatty foods from the diet.

A study is being conducted for patients with atherosclerosis, hypertension, coronary heart disease, cerebrovascular insufficiency, liver and kidney diseases, diabetes mellitus, and thyroid diseases.

Cholesterol levels vary by gender and age. So, for example, for men aged 40 to 45 years, the level of total cholesterol is considered to be from 3.94 to 7.15 mmol / l.

Elevated cholesterol occurs when:

  1. Congenital disorders of fat metabolism.
  2. Atherosclerosis, angina pectoris, myocardial infarction.
  3. Stagnation of bile in cirrhosis of the liver and obstructive jaundice.
  4. Glomerulonephritis and renal failure.
  5. Chronic pancreatitis and tumors of the pancreas.
  6. diabetes mellitus.
  7. Decreased pancreatic function.
  8. Obesity.
  9. Pregnancy.
  10. Taking diuretics, contraceptives, male sex hormones, aspirin.
  11. With gout.
  12. Alcoholism.
  13. With the abuse of fatty or sweet foods.

A drop in cholesterol levels can be a diagnostic sign:

  • Starvation.
  • For burns.
  • In the last stages of cirrhosis of the liver.
  • With sepsis.
  • Hyperthyroidism.
  • Heart failure.
  • Lung diseases.
  • Tuberculosis.
  • Taking drugs to lower cholesterol, estrogens, interferon, thyroxine, clomiphene .

In order to control the content of glucose and cholesterol in the blood in case of impaired metabolism, you can use the express diagnostic method by purchasing test strips and measuring devices.

This is especially important for determining the effect of treatment and selecting the optimal dosage of drugs, since both an increase in the level and a sharp drop are dangerous for the body. The video in this article will just tell you what can affect the results of the tests.

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