Conscientious preparation for donating blood 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, algorithm of actions
A biochemical blood test is taken by a medical laboratory worker in he althcare facilities. For analysis, venous blood from the cubital vein is required. The patient sits on a chair or couch, the arm above the elbow is pinched with a special rubber or plastic tourniquet.
The puncture site is disinfected and the needle is inserted into the vein. Collect the required amount of blood in a test tube. The puncture site is disinfected again. The patient is advised to hold the arm in a bent position at the elbow for several minutes. The manipulation lasts approximately two minutes. The timing of the research will depend on laboratory tests. Routine chemistry results are ready the next day.
Some features of the preparatory phase
The rules for preparing for a biochemical blood test depend on what parametersdoctor wrote directions:
- Lipid spectrum and cholesterol levels. Blood sampling is carried out only after 14 hours of fasting. For 15 days, in agreement with the attending physician, the use of drugs that affect lipid metabolism is excluded. If it is necessary to evaluate the effectiveness of drug therapy, 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, meat products should be abandoned for three days.
- A hormone that affects growth factors or anti-Mullerian hormone, glycoprotein or inhibin B. Testing for these hormones is done between the third and fifth day of menstruation. Three days before the analysis, physical activity is not recommended. Stop smoking one hour before the test. During illness, especially in the acute phase, it is better not to take the test.
- In preparation for a biochemical blood test for ACTH hormones, cortisol, it is supposed to exclude alcohol-containing drinks, physical activity, smoking, stressful situations, taking contraceptivesdrugs, estrogens and glucocorticoids. 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 am.
- Bilirubin. On the eve of the study, do not consume vitamin C and products that can stain the blood serum.
- Sex hormones. The exact time of taking blood for this type of hormones is indicated by a 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 doubt, the study is re-scheduled. For diagnostic purposes, the analysis is carried out before the start of treatment with antibiotics. To evaluate the effectiveness of therapy, blood is taken no earlier than 14 days after the completion of the course of treatment.
Allergy testing
Diagnosis of allergic reactions requires special preparation for blood sampling for biochemical analysis:
- for 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 elimination of false positive results, it is necessary not to take anti-allergenic drugs 7 days before the test;
- research is being done on an empty stomach.
Of the contraindications, it should be noted: the acute period of the disease, menstruation,antibiotic therapy.
Eating
Preparing a patient for a biochemical blood test includes the exclusion of food intake before manipulation. Nutrients absorbed in the intestine after eating:
- change the concentration of carbohydrates, fats, proteins, hormones and other substances;
- activate enzymes;
- increase or decrease blood viscosity.
As a result, the results of the blood test will be unreliable.
It is considered ideal to take the test in the morning after a night's sleep - on an empty stomach. If there are certain difficulties in fulfilling this rule, then the following points must be adhered to:
- do not eat fried foods for two days;
- avoid caffeinated drinks for 24 hours;
- dine should be light on the day before the test;
- do not eat fatty foods at least 4 hours before the test, as a high concentration of fatty substances in the blood distorts the result;
- do not consume carbonated, milk (lactic) 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 a heavy meal (feast).
Preparing for a biochemical blood test: taking medications
The influence of many drugs on the results of laboratory tests, including biochemicalblood test, 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 body of a particular individual and the presence of chronic diseases.
In order for the doctor to be able to correctly interpret the results obtained in the laboratory, you should warn the medical worker about the medications you are taking. It is advisable to discuss with your doctor in advance the possibility of stopping certain medications for a while.
Emotional state and physical activity
Preparation for a biochemical blood test of an adult depends on his emotional state, 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 the analyzes.
Physical activity also activates the internal systems of the body, especially the hormonal and enzymatic ones, and, as a result, the number of biologically active substances in the circulatory system increases, the metabolism is more intense, and the internal organs work more actively. To maximize the exclusion of the influence of the above factors in preparation forbiochemical blood test is desirable:
- exclude any physical activity and sports;
- keep the emotional background in a state of balance: do not allow a strong explosion of emotions;
- immediately before the manipulation, it is recommended to sit quietly and relax.
Bad habits
Alcoholic drinks affect all processes occurring in the body of the individual. The decay products of alcohol-containing drinks adversely affect the work of the body's enzyme systems, affect water-s alt metabolism and cellular respiration. Smoking affects the tone of the vascular system, enhances the functioning of the nervous system, increases the concentration of hormonal substances.
All these processes lead to significant changes in the biochemical parameters of the blood. In order to reduce the harmful effects in preparation for a biochemical blood test, it is recommended:
- do not smoke 30-60 minutes before the test;
- 72 hours in advance – no alcoholic beverages.
Female physiology
The physiological state of a woman is subject to change during the month. 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 gestational age. This is due to a significant change in the concentration of both sex hormones and their metabolites.
Pregnancy also affects the final results of research, 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 changes: proteins, enzymes, hormones and others. How to take a biochemical blood test? Preparation for it is determined by the gynecologist individually for each woman.
Time 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 will allow the doctor to make a diagnosis and prescribe the appropriate treatment.
