Conscientious preparation for blood donation for biochemical analysis is an opportunity to get the most reliable result. There are no contraindications to this type of research.
How to take the analysis, the algorithm of actions
A biochemical blood test is taken by a medical laboratory worker in health facilities. For analysis, venous blood from the cubital vein is required. The patient sits on a chair or couch, a hand above the elbow is clamped with a special rubber or plastic band.
The puncture site is disinfected and a needle is inserted into a vein. Collect the required amount of blood in a test tube. The puncture site is again disinfected. The patient is recommended to hold his arm bent at the elbow for several minutes. The manipulation lasts about two minutes. Laboratory tests will determine the timing of the tests. The results of a routine biochemical analysis are ready the next day.
Some features of the preparatory phase
The rules for preparing for a biochemical blood test depend on what parameters the doctor has prescribed directions:
- Lipid spectrum and cholesterol level. Blood sampling is carried out only after 14 hours of hunger. For 15 days, in agreement with the treating doctor, the administration of drugs that affect lipid metabolism is excluded. If it is necessary to evaluate the effectiveness of drug therapy, the drugs are not canceled.
- Urea. For two days, it is advisable to adhere to a certain diet: exclude offal (kidneys, liver), minimize the intake of meat, fish products, tea and coffee. Physical activity should be moderate.
- Uric acid. A couple of days before the study, follow the recommendations indicated in the previous paragraph. In addition, the following medications are subject to mandatory exclusion: antibacterial and sulfa drugs, salicylates, caffeine, vitamin C, thiazole derivatives, theobromine and theophylline.
- Alfa-2-macroglobulin. Before a blood test for this indicator for three days should abandon meat products.
- A hormone that affects growth factors or anti-mullers hormone, glycoprotein or inhibin B. Analysis of these hormones is carried out between the third and fifth day of menstruation. Three days before the analysis, physical activity is not recommended. Exclude smoking one hour before the study. During diseases, especially in the acute phase, it is better not to take the analysis.
- In preparation for a biochemical blood test for ACTH hormones, cortisol, it is assumed that alcohol-containing drinks, exercise, smoking, stressful situations, the use of contraceptives, estrogens and glucocorticoids are excluded. The best time to get reliable and informative results is no later than two hours after a night's sleep and no later than 10 a.m.
- Bilirubin. On the eve of the study, vitamin C and products that can stain blood serum are not consumed.
- Sex hormones. The exact time of taking blood for this type of hormone is indicated by the gynecologist, depending on the physiological state of the woman (menopause, pregnancy, menstruation).
- Analysis for the detection of infectious diseases can be false positive. To eliminate doubts, the study is re-prescribed. For diagnostic purposes, the analysis is carried out before treatment with antibiotic drugs. To assess the effectiveness of therapy, blood is taken no earlier than 14 days after completion of the course of treatment.
Allergy Analysis
To diagnose allergic reactions, special preparation for blood sampling for biochemical analysis is required:
- 2 days completely exclude alcohol, drugs (as agreed with the doctor), biologically active substances, including vitamins;
- the study is not carried out in cases of treatment with cytostatics, hormones and radiation therapy, since in this case the synthesis of immunoglobulin is inhibited;
- for reliability and exclusion of false positive results, it is necessary not to take anti-allergenic drugs 7 days before the test;
- the study is carried out on an empty stomach.
Of the contraindications, it should be noted: an acute period of the disease, menstruation, antibiotic therapy.
Eating
Preparing the patient for a biochemical blood test includes the exclusion of food intake before manipulation. Nutrients absorbed in the intestines after eating:
- change the concentration of carbohydrates, fats, proteins, hormones and other substances;
- activate the work of enzymes;
- increase or decrease blood viscosity.
As a result, the results of a blood test will be unreliable.
Ideal is the test in the morning after a night's sleep - on an empty stomach. If there are certain difficulties to comply with this rule, then you must adhere to the following points:
- do not eat fried foods for two days;
- exclude the use of caffeinated drinks in 24 hours;
- on the day before the test, dinner should be light;
- at least 4 hours before the test, do not eat fatty foods, since a high concentration of fatty substances in the blood distorts the result;
- do not consume carbonated, dairy (lactic acid) and coloring drinks, juices. Water has little effect on the final result, but it is better to refrain from taking it;
- do not take a biochemical blood test after heavy consumption of food (feast).
Preparation for a biochemical blood test: taking medication
The influence of many drugs on the results of laboratory tests, including a biochemical blood test, has been studied in detail. However, it is impossible to predict in advance how the result of research will change, taking into account the individual characteristics of the organism of a particular individual and the presence of chronic diseases in him.
In order for the doctor to be able to correctly interpret the results obtained in the laboratory, a medical professional should be warned about the medications taken. It is advisable to discuss with the doctor in advance the opportunity to stop taking certain medications for a while.
Emotional state and physical activity
Preparation for a biochemical blood test of an adult depends on his emotional mood, since any stressful situation affects the human body. Under stress, the sympathoadrenal component of the neurohumoral regulation system is activated, which, in turn, leads to increased production of hormones and enzymes, leading to a change in the activity of the internal organs of the individual. The whole complex of these processes affects the results of analyzes.
Physical activity also activates the internal systems of the body, especially the hormonal and enzyme ones, and, as a result, the number of biologically active substances in the circulatory system increases, metabolism is more intensive, and internal organs work more actively. To maximize the exclusion of the influence of the above factors in preparation for a biochemical blood test, it is desirable:
- exclude any physical activity and exercise;
- to keep the emotional background in a state of balance: not to allow a strong explosion of emotions;
- Immediately before the manipulation it is recommended to calmly sit and relax.
Bad habits
Alcoholic beverages affect all processes occurring in the body of an individual. The breakdown products of alcohol-containing drinks adversely affect the work of the enzyme systems of the body, affect water-salt metabolism and cellular respiration. Smoking has an effect on the tone of the vascular system, enhances the nervous system, and increases the concentration of hormonal substances.
All these processes lead to significant changes in the biochemical parameters of blood. In order to reduce the harmful effects in preparation for a biochemical blood test, it is recommended:
- 30-60 minutes before taking the test do not smoke;
- in 72 hours - exclude the use of alcohol-containing drinks.
Female physiology
The physiological condition of a woman within a month is subject to change. A biochemical blood test for such an indicator as hormones (follicle-stimulating, luteinizing, estradiol, prolactin, progesterone, androstenedione and others) is recommended to be taken on a certain day of menstruation or during pregnancy. This is due to a significant change in the concentration of both sex hormones and their metabolites.
Pregnancy also affects the final results of studies, since during this period hormonal changes in the body occur, and depending on the duration of pregnancy, the concentration of a number of substances in the body: proteins, enzymes, hormones, and others. How to take a biochemical blood test? Preparation for it is determined by the gynecologist individually for each woman.
Times of Day
There are some types of biochemical indicators, the value of which depends on the time of day, for example, specific markers of metabolism in bone tissue. If the doctor prescribes this analysis for the purpose of monitoring, then it should be taken at the same time.
With proper preparation for a blood test for a biochemical study, the result will be as accurate as possible and allow the doctor to make a diagnosis and prescribe the appropriate treatment.