A general blood test is a basic test prescribed by doctors of various specialties when a patient comes in for an examination. If you have complaints of feeling unwell, your doctor is likely to prescribe a general blood test. The results of the test will give him or her a general idea of your state of health and allow him or her to decide what direction to take, such as what tests are still needed to make a diagnosis.
How to prepare for the blood test
It is best to perform a blood test before you start taking medications or 10-14 days after they have been discontinued. The nurse and the doctor who performs the diagnosis or prescribes treatment should be informed about the medications you are currently taking.
Rules of preparation for the test:
- Blood is drawn in the morning, on an empty stomach. The optimal time is between 8 and 11 o’clock.
- At least a week before the test, you should avoid alcohol and intense physical activity.
- 8 hours before the test you can have a light, lean meal.
- 1-2 hours before the test it is desirable not to smoke, avoid stress and physical exertion (running, rapid ascent of stairs).
- 15 minutes before the blood draw it is useful to sit in the laboratory department for a while, to breathe and calm down.
It is possible to take a general blood test at your own will, and doctors also prescribe this study when:
- general medical examinations (medical check-ups);
- symptoms of inflammatory or infectious processes, including ARVI – to determine the “culprit” (virus or bacteria);
- general indisposition of the patient (weakness, rapid fatigue, lethargy, various pains, etc.) in the process of diagnosis;
- preparation for surgery;
- suspected worm infestation;
- pregnancy;
- preparation for vaccination, etc.
Deciphering the indicators of the general blood test
- Hemoglobin
Hemoglobin is a protein that makes up part of the red blood cell. Hemoglobin binds to oxygen and carbon dioxide molecules, allowing oxygen to be transported from the lungs to tissues throughout the body and carbon dioxide to be transported back to the lungs. Hemoglobin contains iron in its composition. It is it that gives red color to red blood cells (red blood cells), and already those – blood.
Blood hemoglobin saturation is an extremely important indicator. If it falls, the tissues of the body receive less oxygen, and oxygen is necessary for the vital activity of every cell.
The norm of hemoglobin for men is 130-160 g / l, in women – 120-140 g / l.
When hemoglobin values are lower than normal, anemia is diagnosed. Also, a low hemoglobin level can indicate hyperhydration of the body (increased fluid intake). Hemoglobin above normal, respectively, can be observed in dehydration (blood clotting). Dehydration can be physiological (for example, due to increased physical activity), and can be pathological. Elevated hemoglobin is a typical sign of erythremia, a blood formation disorder in which an increased number of red blood cells are produced.
- Erythrocytes
Erythrocytes are red blood cells. They are much more numerous than all the other blood cells combined. That is why our blood is red in color. Erythrocytes contain hemoglobin and thus participate in the process of oxygen metabolism in the body.
The norm for red blood cells for men is 4-5*1012 per liter of blood, for women – 3.9-4.7*1012 per liter.
Reductions in the content of erythrocytes in the blood are observed in anemia, bleeding, pregnancy, hyperhydration. Exceeding the norm may indicate dehydration, erythremia, tumor formations, as well as diseases such as renal cysts or renal pelvic hydrocele.
- Reticulocytes
Reticulocytes are young, immature forms of red blood cells. The process of red blood cell formation is continuous, so reticulocytes are always present in the blood. Normal: 2-10 reticulocytes out of 1000 red blood cells (2-10 ppm (‰) , or 0.2-1%). If reticulocytes are higher than normal, it indicates that the body feels the need to increase the number of red blood cells (for example, because of their rapid destruction or blood loss). A decreased level of reticulocytes is characteristic of anemia, radiation sickness, oncology, and some kidney diseases.
- Platelets
The main function of platelets is to provide hemostasis, i.e., simply put, platelets are responsible for blood clotting. They also participate in the body’s immune response to the penetration of infection. Norm: 180-320*109 per liter. A decreased level of platelets may indicate a severe inflammatory process or autoimmune disease. An elevated level is characteristic of conditions after significant blood loss (e.g., after surgery), and is also seen in cancer or spleen atrophy.
- Leukocytes
Leukocytes are white blood cells that perform a protective function, i.e. represent the immune system. Normally, the total number of leukocytes in a blood test should be in the range of 4-9*10⁹ per liter.
An increase in the number of leukocytes indicates the immune response of the body and is observed in infectious diseases (primarily caused by bacteria), inflammatory processes, and allergic reactions. High levels of leukocytes can also be a consequence of recent bleeding, stress, tumor processes, and some other pathologies.
A decreased level of leukocytes indicates a depressed state of the immune system. Such results can be observed with viral infection (influenza, measles, rubella), severe toxicosis, sepsis, diseases of the hematopoietic organs, radiation sickness, autoimmune diseases, etc.
It is not only the general assessment of the leukocyte count that is of significance. There are five types of leukocytes and they all have different functions, so it is important to know in what ratio they are represented in the composition of the blood test. The ratio of different types of leukocytes in their total volume is called the leukocyte formula.
- Lymphocytes
Lymphocytes are the main cells of the immune system. They provide specific immunity, i.e. they recognize an invading foreign agent and destroy it. With the help of lymphocytes, the body fights viruses. In the norm, lymphocytes make up 19-37% of the total number of leukocytes. In children, the proportion of lymphocytes is greater.
Increased content of lymphocytes in the blood test indicates the penetration of viral infection, and is also noted in toxoplasmosis, tuberculosis, and syphilis.
A decreased number of lymphocytes in the blood test is a sign of a depressed state of the immune system.
Conclusion
Blood test analysis is an important diagnostic tool that allows you to identify a wide range of diseases. According to its results, you can determine anemia, inflammatory processes, infections, immune problems, blood coagulation disorders, and even cancer. Proper preparation for the study helps to obtain reliable results. In case of deviations from the norm, the doctor can prescribe additional examinations to clarify the diagnosis and the choice of treatment tactics. Regular monitoring of blood test counts plays a key role in maintaining health and early detection of possible pathologies.
