Prescribing a general blood test is a long-established tradition for the vast majority of doctors of any specialty. A general analysis allows you to estimate the number of formed elements, namely red blood cells, platelets, leukocytes (without subtleties and fractions of various types), hemoglobin level and erythrocyte sedimentation rate (ESR).
The analysis is quite simple, however, this information is enough to suspect an inflammatory process, see anemia, and in some cases, suspect blood cancer or other stem cell pathology.
A complete blood count is a guideline for many subsequent tests and diagnostic procedures, so it is important to do it correctly.
How to take a general blood test correctly
A general blood test should be taken following the doctor’s recommendations
Any blood test, incl. general, it is necessary to take it on an empty stomach, i.e. the period between the analysis and the last meal should be more than 8 hours, but less than 14.
Before this, you should not eat spicy and fatty foods, or overeat - this can affect the ESR. In general, the day before taking a general test, it is better to avoid any provoking factors, such as stress, excessive physical activity, dehydration or excessive fluid intake (for any reason).
The results of the analysis can be affected by various medications, some of which cannot be canceled (for example, acetylsalicylic acid cannot be canceled for a single day).
Of course, a general blood test cannot be taken in a state of toxic or alcoholic intoxication. The same applies to all varieties of hashish, etc. You need to understand that the half-life of the toxin is important. Your well-being cannot be the criterion in this case - at least 48 hours must pass from the moment of intoxication.
General principles of analysis (photo)
Arrive on time 
No smoking 
Don't drink alcohol 
Take on an empty stomach
It is advisable not to smoke an hour before the general analysis, because smoking reduces the number of eosinophils in the general blood pool, i.e. affects the indicator “number of leukocytes”.
You should not take the test “on the run”, i.e. It is advisable to sit and calm down for 15 minutes before the test.
It happens that with full compliance with the above principles, the results are distorted, which becomes clear a little later. This can lead to the fact that the correct diagnosis eludes the doctor for a long time, and the patient will waste time and money searching for a non-existent problem. The second unpleasant moment is the illusion of the absence of a pathological condition, which arose due to a number of factors not taken into account before the analysis.
Factors influencing the results of the analysis
Fear of the procedure greatly affects the results
We will not analyze laboratory errors (this is a separate topic for discussion); we will only describe factors on the part of patients that can lead to an erroneous interpretation of a general blood test.
Fear of doctors, tests, scarifiers. Formed since childhood. Due to the release of adrenaline, cellular elements (primarily red blood cells) leave the blood depot (liver, etc.). As a result, the number of blood cells and the level of hemoglobin in the blood increases, the doctor observes polycythemia and refers the healthy patient to a hematologist. The second option is that a patient with stomach bleeding, for example, due to stress, shows a normal hemoglobin level, he is sent home to “drink vitamins”, after which massive anemia develops with hospitalization and other unpleasant outcomes.
If you are afraid of all these people in white, as well as their scary instruments, warn your doctor about this in advance (or go for tests with your loved ones).
Complete blood count may change in pregnant women
Heavy menstrual bleeding(like any others) can also distort the results of a general blood test. It is advisable to take the test only 4-5 days after their completion.
The time during which the test must be taken must fall between 7:00 and 9:00 (morning). This is connected not only with the order of operation of health care facilities (which can be overcome if desired), but also with the actual biorhythms of the human body. Blood counts can change quite noticeably throughout the day.
If you are taking any painkillers or anti-inflammatory drugs, tell your doctor. Such substances conceal signs of inflammation, therefore (if possible) they are discontinued a week before the expected date of analysis.
To diagnose a person's health, it is often necessary to take a general blood test. This is a very common procedure that helps to quickly identify possible diseases and malfunctions of the body’s organs. Here specialists can quickly monitor the level of monocytes, leukocytes, red blood cells and hemoglobin.
Preparation
Donating blood must follow special rules. This is necessary to obtain accurate results. This procedure begins with preliminary preparation. The first step is to find out if you are taking additional medications that could affect or skew the results. To do this, it is better to consult a doctor to get the most accurate data. As a rule, blood is donated on an empty stomach. This means that you should not even drink coffee or tea in the morning, especially with sugar, without which many cannot imagine starting the day. Particular attention should be paid to women, as their results may be affected by the menstrual cycle and gestational age.
Submission rules
For analysis, blood is given in the morning, usually from 7 to 11 o'clock. You can drink water, but without any additives. All other products are strictly excluded. It is also not recommended to consume spicy foods, fatty foods, alcoholic drinks the day before the test, and you should not overeat. Excessive physical activity is undesirable, since after it the body absorbs many substances from the blood, which can show their deficiency. If blood must be taken not in the morning, then after the last meal it should be approximately eight hours. This will show reliable levels of cholesterol, triglycerides and other lipids.
From a vein or from a finger?
For standard tests, blood is taken from a finger. This is a simple and relatively painless procedure. For most analyses, it is quite sufficient. When blood is taken from a vein, this is done for more detailed tests. The process itself takes only a few seconds.
In the process of diagnostic examination of a patient, one of the first things to be examined is blood - a liquid substance of the internal environment of the body, reflecting its condition. There is a clinical study for this called a complete blood count (CBC).
The result of the OAC is not one parameter, but a whole set of indicators, therefore, despite the small amount of blood taken for research, it can give a completely detailed picture of the pathological changes developing in the body. That is why a general blood test not only should not be neglected, but one should also prepare for it so that the final results are not distorted.
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Preparing for blood sampling for a general analysis involves abstaining from eating 8-12 hours before the procedure. Many doctors still adhere to precisely these training rules. But in modern conditions, it has long been practiced to collect blood not strictly on an empty stomach, but after a light breakfast. Usually the decision - whether to fast or not - is made by the doctor who gives a referral for a blood test.
Why do they take it on an empty stomach?
Experts who support fasting blood sampling explain their position by the fact that some blood parameters increase after eating, reacting even to a cup of sweet tea. This rule unconditionally applies to OAC if blood is taken from a vein, which is why in this case it is donated on an empty stomach. Many modern laboratories take only venous blood for analysis, so they recommend that their patients refrain from eating food 8-12 hours before taking the sample; during this time, even drinking or juice is prohibited; only plain water is allowed.
You can donate venous blood only on an empty stomach; it is not recommended to have breakfast, so as not to distort the results.
Can I take it after eating?
If capillary blood (from a finger) is taken for analysis, then there are no restrictions on food consumption and you are allowed to have breakfast in the morning. This can be done even immediately before visiting the laboratory.
Capillary blood collection
What happens if you have breakfast before the test?
In order to donate blood correctly, an adult (whether a woman or a man) or a child should follow the recommendations given by the doctor. When a doctor requires a fasting blood sample, you should not check what will happen if this requirement is ignored. Each body reacts differently to the supply of nutrients, and even a slight distortion of the results can lead to the need to take the test again. You should also not smoke at least 1 hour before the procedure.
If the doctor said that it is not necessary to eat breakfast, you can have breakfast, you should eat a small portion of breakfast without sugar and fat.
To monitor the dynamics of the disease or the effectiveness of therapy, you should donate blood either strictly on an empty stomach, or every time after a light breakfast, and in all cases, the blood should be either only venous or only capillary.
If you have to take a general blood test several times during one illness, this should be done under the same conditions.
Where do you get clinical CBC from?
The results of the study are not affected by where the blood is taken for clinical analysis. Many laboratories find it more convenient to take blood from a vein.
Devices such as scarifiers have not lost their relevance either. They are designed to pierce the pad of the ring finger, where capillary blood is taken. Scarifiers must also be sterile, individually packaged and disposable.
Metal scarifier
A more modern version of the piercing device is the so-called lancets. These medical products are more expensive than scarifiers. They resemble plastic fountain pens with springs inside, ensuring that a sharp needle “shoots” from the rod strictly to a certain depth. Lancets are most convenient when you have to donate blood to a child, since, thanks to the special sharpening of the needle, they ensure almost complete painlessness of the manipulation.
How to prepare a child for the OAC test?
The pediatrician who gives the referral usually tells your child in advance how to properly donate blood for a general test. If you intend to collect blood in the laboratory of a private clinic, it is advisable to familiarize yourself with the rules for donating material adopted in a particular medical and diagnostic institution. Usually, the memo also contains guidelines explaining how to give it to a child - on an empty stomach or not, from a finger or from a vein, and whether preliminary preparation is needed. In general terms, the rules are simple.
- You should prepare for going to the laboratory in advance - 1-2 days before the OAC, you should tell your child about the emergency procedure and how it is necessary.
- It is advisable for young children to take their favorite toy, book or album, and markers for drawing with them so that they do not concentrate on fear while waiting for the procedure.
- First of all, the mother herself should get rid of fear, since children very keenly feel the state of their own adult; there is no need to intimidate the child.
- It is advisable to mentally prepare children of older preschool and school age for the upcoming event, explaining that it may be a little painful, but it is necessary and will not last long, so he will be able to endure it.
- Most laboratories recommend taking a clinical test strictly on an empty stomach, so you should not feed your child 8 hours before taking blood. For children 1-5 years old, the period of abstinence is 2-3 hours.
- It is worth taking a tasty and nutritious snack for your child to the laboratory so that you can feed him after leaving the treatment room.
After the procedure, it is advisable to reward the child for his persistence and at the same time to smooth out unpleasant impressions of the clinic or laboratory.
How is blood taken from a baby and how to prepare for the test?
Although today few mothers adhere to a strict feeding regime, on the day when the baby needs to donate blood for a general test, it is worth calculating the feeding time so that the OAC procedure falls on the period between the first and second feeding.
Before entering the office, warm the baby’s hands so that they are always warm.
It is imperative for the mother not to worry, not to fuss, not to get nervous over trifles, the procedure is simple, does not require much time, everything will be over before the child has time to get scared. This attitude has a very positive effect on the child and greatly facilitates the manipulation.
How often does this test need to be done?
Those who are interested in how often they need to donate blood for a general analysis should decide why these studies are being carried out. The need to donate blood to a child or adult usually arises when pathological conditions are suspected:
- when the temperature rises;
- malaise, body aches;
- the appearance of a rash and other changes on the skin;
- general weakness and other symptoms of disease.
It is advisable to obtain a referral for a planned (preventive) general analysis from a doctor, who will interpret the results and notify the patient about them.
Early diagnosis of absolutely any disease begins with testing. Their range is wide, more and more new laboratory diagnostics appear every year, but a general blood test remains mandatory and unchanged for any examination. Every patient is interested in correct and informative research results. How accurate the forecasts you get depends directly on your preparation for the analysis. That’s why it’s so important to know how to take a general blood test, so that you don’t have to run around to different laboratories in search of the truth.
A general blood test is taken in the laboratory at the clinic, where your attending physician should refer you after studying your medical history. This procedure has been mandatory for many years for those who come to a medical facility with complaints of poor health.
Why take a general blood test?
CBC (complete blood test) is a simple and proven way to determine a person’s condition through his blood. This study is aimed at assessing the functioning of the main serum components, of which there are more than a hundred. A malfunction or change in the parameters of at least one shaped element of a biomaterial may indicate either a minor deviation in the body or serious pathologies in the progression stage.
Blood is donated for this study in the following cases:
- to identify microorganisms that are hostile and create an unfavorable environment;
- assess the state of the human immune system;
- determine the level of hormone concentrations in the blood;
- examination of all blood components to identify hidden or obvious health problems.
You do not have to be sick to undergo this type of examination. This analysis is mandatory for pregnant women, people undergoing a commission for employment, in the case of an annual scheduled examination. Often the CBC becomes the main test for people with chronic illnesses. This is the only way to constantly monitor their health status.
The first days of a newborn’s life are also accompanied by taking blood for a clinical test to assess the baby’s general condition and identify possible abnormalities at an early stage.
In any case, a referral for testing is issued by the attending physician. During hospitalization, the procedure for taking biomaterial will be carried out directly within the walls of the hospital.
