Is it possible to drink water before donating blood - this question is asked by the vast majority of citizens who will have to take this analysis. At the same time, only a few people know objective and reliable information about preparing for a blood test, and the information received from the attending physician is too general.

Preparation for the delivery of the analysis

This type of analysis is a collection of a limited amount of blood for chemical analysis of its composition. According to the purpose of the study, a blood test is of the following types:

• biochemical study (for biochemistry) - allows you to evaluate the work internal organs human, the state of metabolism;
• general blood analysis;
• sugar test - allows you to determine the level of glucose in the blood, which is a decisive indicator in the diagnosis and treatment of diabetes.

The general rule that every treating physician must communicate to the patient before issuing a referral is that it is necessary to take tests on an empty stomach. This implies that no food should be consumed before the blood test, so as not to cause chemical reaction metabolism that affects chemical composition blood.

To fulfill the rule of taking tests on an empty stomach, the attending physician will always clarify how much you can’t eat and what you can do in preparation for blood sampling. Questions “why not” and whether it is possible to drink water, as a rule, are not asked.

Let's define the basic rules before donating blood from a vein and from a finger. It is strictly forbidden to consume any kind of food, and the last meal should be no later than 8-12 hours before blood sampling. It is this period of time that takes the complete process of assimilation of food, after which the chemical composition of the blood returns to its usual state for the body.

This rule also applies to a biochemical blood test, and the minimum period of time after eating cannot be less than 8 hours.

In practice, the attending physician recommends limiting food intake in the evening before the test. This period of time will be at least 8 hours, and ideally - 12 hours. This time is quite enough to bring the state of the blood into a state that allows an objective assessment functional state body and metabolism.

To prepare for the delivery of a general blood test, it allows relaxation regarding the time of eating - the minimum period of time should not be more than 1-2 hours, and the composition of the products should also correspond to the instruction of the attending physician.

When preparing for blood sampling, any food containing nutrients is excluded. These products even include fruit juices, tea and coffee, so the doubts “is it possible to drink tea or coffee” should be forgotten once and for all. It is strictly forbidden to drink alcohol 1-2 days before the proposed blood test, since the residual content of alcohol in the blood lasts longer than the nutrients in food.

Can I drink water before taking blood?

One question remains - is it possible to drink ordinary drinking water when you donate blood? Medicine does not contain any prohibitions regarding the use of pure water, since its chemical composition is not able to directly affect the blood test.

We are talking about ordinary drinking water, not enriched with additional ingredients (artificial sweeteners, colors, etc.).

What will you feel while studying?

The most commonly used screening urine extraction methods. Best for microbiological testing and sediment is the first morning urine. 24-hour urine - used to study clearances or to determine the excretion of protein, electrolytes and other ingredients. Separate portions of urine are collected in a well-washed container and the amount is measured within 24 hours. If the terminal, respectively, is bleeding from Bladder or kidneys.

• Upon awakening, the patient urinates and discards the first urine of the day.
• From that moment, the collection began within 24 hours.

There is no discomfort in this study.

Moreover, some doctors even recommend taking a limited amount of water with you to the laboratory, since taking it before blood sampling can calm the patient's condition and relieve unnecessary nervousness. In the memo that patients receive before they are sent for testing, they usually do not write about drinking water, limiting themselves to a list of foods and drinks, the use of which is strictly prohibited.

However, there are certain types of blood tests in which it is forbidden to drink even plain water. These analyzes include:

• blood chemistry;
• blood test for hormones;
• blood test for AIDS or HIV infection.

Such a requirement is due to the inadmissibility of even the slightest influence of extraneous factors on the state of the blood for these tests. Water is made up of chemical elements, and therefore, theoretically, can create an error in the study of biochemical or hormonal parameters.

Since the chemical parameters of blood directly depend on environmental factors and a person’s lifestyle, before taking any type of blood test, you must be in a calm state, completely eliminate physical exercise or stressful situation. Also, for blood sampling, only morning time days when the composition of the blood is in its original state and is best suited for research.

For clinical trial there is a ban on the use of blood medicines, except in cases where the attending physician prescribes a blood test to determine the effect of the drug on the patient's body condition.

Thus, instead of following myths and conjectures, preparation for blood sampling should be carried out taking into account the recommendations of the attending physician. If questions arise, they should be asked to the doctor when issuing a referral, and not to the laboratory assistant when passing the analysis. In addition, each specific type of blood test has its own special restrictions on the permissible use of food and drink.

Modern medicine cannot be imagined without blood tests. They are necessary to correctly diagnose and prescribe treatment. According to the World Health Organization, laboratory diagnostics provides up to 80% of information about the state of health of the human body. The reliability and accuracy of the test result depends both on the technical level of equipment of the laboratory, the professionalism of the laboratory assistant, the correct blood sampling by the average medical staff, and from the patient's compliance with the limited rules for preparing for blood donation.

Getting ready for testing

For a biochemical blood test or to determine the level of hormones, at least 2 ml of blood must be taken from the patient. Such an amount of the test material can be collected only from a vein. And if the blood sampling is carried out correctly, then already at this stage the probability of damage to the integrity of blood cells is significantly reduced. And this, in turn, affects the final results of the analysis.

The main condition is to donate blood on an empty stomach

Almost all blood tests are taken strictly on an empty stomach. For example, biochemical studies are performed on blood glucose, lipid spectrum, urea, creatinine, bilirubin, hormones, and others. In order to take fasting blood tests, the last meal before blood sampling should take place eight hours before the procedure. And for taking a blood test for the lipid spectrum (cholesterol, triglycerides, high and low density lipoprotein cholesterol) - eating at least twelve hours in advance.

Can I drink juice, tea, coffee before taking the test?

Unfortunately, you can’t drink juice, tea, coffee, these drinks affect blood counts and it is not recommended to use these drinks. However, you can drink plain water. It is also necessary to exclude fatty, fried and alcohol from the diet two to three days before the examination. If a festive feast took place the day before, it is advisable to postpone the laboratory test for one or two days, and refrain from smoking an hour before taking blood.

To determine the true level of blood lipids, it is necessary to exclude the use of animal fats, caviar, cheese, sausage, egg yolk a week before the test. If this is not done, then lipid levels will be elevated due to the intake of these ingredients with food in the body.

Complete or complete blood count

If you have to take a detailed or general blood test (from a finger), then the last meal should be 1 hour before the procedure and may consist of unsweetened tea, unsweetened porridge without milk, butter and apple.

Blood for infectious diseases

Some blood tests do not require strict restrictions. Donate blood for the presence of antibodies to HIV, viral hepatitis, rubella, cytomegalovirus and others infectious diseases can be in the morning, afternoon or evening without prior fasting. Since the patient has already been infected, the concentration of antibodies to the infection in his blood remains stable at any time of the day, as well as before, during or after meals.

Tests for hormones

The content of hormones in the blood is subject to diurnal (circadian) fluctuations, therefore, blood for the determination of TSH, parathyroid hormone, and iron is taken on an empty stomach strictly before 11 am, and blood cortisol is determined at 8.00 and 20.00. It is necessary to study the level of hormones always at the same time. In this case, the dynamics of the obtained results will be more correct. To correctly determine the level of TSH in dynamics during the treatment of hypothyroidism, it is necessary to donate blood before taking replacement therapy.

• Taking blood for analysis before admission medicines (for example, antibiotics and chemotherapy drugs) or not earlier than 10-14 days after their withdrawal. Be sure to tell your doctor if you are taking medication.

• Before taking blood, you need to rest for 10-15 minutes in the waiting room and calm down. If you're nervous, it can affect your blood sugar levels.

• When examining for the presence of infections, it should be borne in mind that, depending on the period of infection and the condition immune system any patient can have a negative test result, but it does not completely rule out infection. In doubtful cases, it is recommended to re-examine after a while, but not earlier than after three to four weeks.
• In hormonal studies in women of reproductive age (from about 12-13 years old to the onset of menopause), the results are influenced by physiological factors associated with stage menstrual cycle . Therefore, to determine the level of FSH and LH, they are taken on the fifth to seventh day of the menstrual cycle. To determine the level of estradiol and progesterone - for 21-23 days.
• To reduce the likelihood of a hematoma (bruise) at the vein puncture site after blood sampling, it is necessary bend your arm at the elbow and hold for 15 minutes. In the evening, make a compress with a half-alcohol solution for 15-20 minutes.
• If, when taking blood for a laboratory test, you experience fear, dizziness, weakness, are afraid of losing consciousness, warn the procedural sister in advance, and the blood will be taken from you in the supine position.
• Many laboratories can conduct an anonymous test, but if you want an official result, bring your passport with you.
• Anonymous results are not accepted during hospitalization, at the OVIR, embassies and some other places.

Remember that an accurate picture of the state of health can be obtained by analyzes carried out systematically. Until the age of 30-40, they should be done annually, and after 40 - once every six months. In the presence of chronic diseases the regularity of examinations can be more frequent - once every three months or even monthly.

A complex of regular laboratory tests allows you to get a timely and reliable assessment of your health status. The complex examination includes the following laboratory indicators. Biochemical analysis blood (11 main indicators), characterizes the state of the functions of the liver, kidneys, carbohydrate, protein and fat metabolism. General analyzes blood and urine, determination of C-reactive protein. These tests will show the presence or absence of inflammatory processes in the body. Analysis for the presence of viral heptitis (HCV, HBsAg).

If there is a deviation from normal values at least one of the indicators, you should consult your doctor.

Remember that it is necessary to consult a doctor in time to draw up an examination plan in accordance with your complaints, objective examination data, comorbidities, and he will help you explain the results of the tests.