Common blood test: decoding, table of normal values, preparation for the test
A clinical (common) blood test is a laboratory examination of the qualitative and quantitative composition of a patient's blood in order to diagnose and detect signs of infection and inflammation in the body. Common blood tests are always prescribed at the first signs of illness, but doctors recommend doing it at least once a year for preventive purposes. The results of the analysis are also entered into the spa treatment card, so no treatment at a spa hotel is prescribed without it.
Subject of study and table of norms
For a common blood analysis, venous or capillary blood is collected, which is examined for the levels of red blood cells, platelets, hemoglobin, erythrocyte sedimentation rate, leukocyte count, hematocrit and a number of other parameters. It is worth noting that for boys and girls under the age of 12, the normal values are the same, and then there is a difference not only from gender, but also from the age of the patient - when interpreting the results, the doctor always makes allowance for this. When taking blood from a vein and from the finger, the results may differ slightly, so for a correct analysis of the dynamics it is recommended to take blood by the same method.
Table of reference values for common blood tests
|
Indicator |
Identification |
Norma (women) |
Norma (men) |
Units |
|
Hemoglobin |
HGB, Hb |
117-155 |
132-173 |
g/l |
|
Mean red cell volume |
MCV, macrocytosis, normocytosis, microcytosis |
78-101 |
80-101 |
fl |
|
Red cell distribution widt |
RDW |
11,6-14,8 |
11,6-14,8 |
% |
|
Total red blood cell count |
RBC |
3.9-5.3 |
4.2-5.6 |
mln/μl |
|
Total platelet count |
PLT, PC, platelets |
150-400 |
150-400 |
thousand/μl |
|
Erythrocyte sedimentation rate |
ESR |
2-20 |
2-15 |
mm/h |
|
Hematocrit |
HCT |
34-47 |
37-50 |
% |
|
Mean red blood cell hemoglobin |
MCH |
27-34 |
27-35 |
pg |
|
Reticulocytes |
RET |
0.5-1.2 |
0.5-1.2 |
% |
|
Total white blood cell count |
WBC |
4.5-11 |
4.5-11 |
thousand/μl |
|
Leukocyte formula |
|
|
|
|
|---|---|---|---|---|
|
Neutrophils |
NEUT |
47-72 |
47-72 |
% |
|
Lymphocytes |
LYM |
19-37 |
19-37 |
% |
|
Monocytes |
MON |
3-12 |
3-12 |
% |
|
Eosinophils |
EO |
1-5 |
1-5 |
% |
|
Basophils |
BAS |
0-1,2 |
0-1,2 |
% |
Interpretation of the common blood test
Before proceeding to the description of the indicators of the common blood test, we emphasise that the following information is of an introductory nature and the interpretation of the results should be dealt with by the doctor. As a rule, diseases are complex and simultaneously affect several blood parameters, the connection between which can only be made by a doctor. Trying to diagnose yourself is fraught with wrong conclusions and, as a consequence, making dangerous decisions for your health. We also draw attention to the fact that 5% of healthy people may have normal values outside of the accepted reference (statistical average) values.
Erythrocytes
Erythrocytes, the red blood cells, perform the function of couriers in the human body. Due to their elasticity they penetrate into vessels of any diameter and transport oxygen from lungs to all organs and tissues, and in the opposite direction they carry carbon dioxide. These gases attach to hemoglobin contained in red blood cells.
High red blood cell counts in the results may indicate dehydration, blood diseases, heart and respiratory problems.
Low red blood cell counts are seen in blood loss, leukemia, lymphoma, congenital hematopoietic disorders, malignant tumors, hemolytic anemia, and protein, iron, and vitamin deficiencies.
Platelets
The main functions of platelets are blood clotting, clot formation, maintenance of vascular wall tone and capillary nutrition.
High levels of platelets in the patient's blood can be interpreted as a consequence of spleen resection, exacerbation of chronic autoimmune diseases, anemia of different origin, inflammatory processes. Platelet count tends to increase in the third trimester of pregnancy, in the postoperative period, in the development of erythraemia and malignant tumors.
A low platelet count may indicate hemophilia, drug-induced thrombocytopenia, systemic lupus erythematosus, renal vein thrombosis, viral or bacterial infection, aplastic anemia, Fisher-Evans syndrome.
Hemoglobin
Hemoglobin is used to assess the severity of anemia or polycythemia and to evaluate the effectiveness of treatment for these conditions. Hemoglobin is an iron-containing protein found in red blood cells that has a gas-exchange function.
An increase in hemoglobin is seen in dehydration, heart and lung failure, diuretic overdose, heart defects, and various blood and urinary system diseases.
Anemia of various etiologies, blood diseases, blood loss, deficiency of proteins, vitamins and iron lead to a decrease in hemoglobin.
Leukocytes
White blood cells are produced by the bone marrow and have a protective function in the human body. They help fight foreign objects in the blood, infections, foreign protein molecules, and dissolve damaged tissue during the inflammation stage.
The number of leukocytes in the total blood count can increase for a variety of reasons of different nature: it could be pregnancy, physical exertion or eating before donating blood, vaccinations, systemic or local inflammation, injuries, burns, autoimmune diseases, conditions after surgery, cancer, leukemias.
Leukocyte count decreases due to viral infections, systemic autoimmune diseases, leukemia, radiation sickness, vitamin deficiencies, and cytostatics and steroids.
Leukocyte formula
The leukocyte formula is a description of the different forms of leukocytes in the blood serum, expressed either quantitatively or as a percentage. The leukocyte population includes 5 cell types: neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
Neutrophils are always represented in the largest numbers, they are the first to "fight" the infection, surround and eliminate bacteria by phagocytosis. The most common reason for an increased neutrophil count in the blood is acute bacterial and fungal infections. Other possible causes of increased neutrophil counts are systemic inflammatory diseases, pancreatitis, myocardial infarction, conditions after burns, and malignant bone marrow tumors. The number of neutrophils decreases in massive bacterial infections, sepsis, viral infections, aplastic anemia, tumor metastases to the bone marrow.
Lymphocytes are indispensable tools of the immune system, without them viruses cannot be destroyed and infections cannot be fought. B-lymphocytes "specialize" in producing antibodies, T-lymphocytes in destroying infected cells, preventing the spread of infection, and detecting and destroying cancer cells. Acute bacterial infections, influenza, aplastic anemia, AIDS, systemic lupus erythematosus, some congenital diseases and taking prednisolone lead to lower lymphocyte levels. Infectious mononucleosis, rubella, varicella and other viral infections, malignant tumors of bone marrow and lymph nodes, and some bacterial infections lead to increased lymphocyte levels.
There are few monocytes in the blood, but they have an important protective function. Monocytes have the ability to turn into macrophages, destroying damaged cells and retaining foreign proteins on their surface, thereby facilitating the work of lymphocytes. Decreased monocyte counts usually indicate aplastic anemia or accompany prednisolone treatment. Increased monocyte concentration is seen in acute bacterial infections, tuberculosis, syphilis, sarcoidosis, connective tissue diseases, and cancers of various localizations.
Eosinophils in the blood are also few relative to other white blood cells, and they also have the ability to phagocytosis, but their main task is to fight parasites and regulate allergic reactions. Increased levels of eosinophils accompany allergic diseases (bronchial asthma, eczema, food allergies), allergic reactions to medications and parasitic worm infestation. A much rarer increase in the number of eosinophils can be explained by the development of malignant tumors in the bone marrow and lymph nodes, systemic connective tissue diseases or Lefler syndrome. The number of eosinophils decreases during treatment with prednisolone, in Cushing's and Goodpasture's syndromes, and in acute bacterial infections.
Basophils, when activated, release histamine, a substance that causes allergy symptoms (itching, burning, redness). The concentration of basophils in the blood test results decreases in the acute phase of an infectious disease, hyperthyroidism, prolonged treatment with corticosteroids. An increase in basophil counts is rare, e.g. in bone marrow and lymph node cancer, true polycythemia, and some allergic diseases.
Reticulocytes
Reticulocytes are young red blood cells produced by the bone marrow. The quantification of reticulocytes in the blood gives an indication of how adequately the bone marrow is producing red blood cells. Reticulocyte levels can be abnormal for extraneous reasons, such as high altitude climbing, scuba diving, smoking, pregnancy, and taking medications.
Bleeding, hemolysis, inflammation, cancer, polycythemia of different etiologies, consequences of radiation therapy and chemotherapy, and side effects of anemia treatment can all lead to an increase in reticulocytes in the results of a general blood test.
Finding low reticulocyte counts may suggest iron deficiency, B12-deficiency, or folate deficiency anemia, thyroid disease, aplastic anemia, kidney disease, chronic infections, and uremia.
Hematocrit
The hematocrit, measured as a percentage, is the ratio of the volume of red blood cells to the volume of liquid blood. Elevated hematocrit is found in iron-, B12- and folate-deficient anemia, bleeding disorders, hemoglobin synthesis disorders, liver cirrhosis, hemolysis, malignant tumors, or due to intravenous administration of significant amounts of fluids. Low hematocrit usually indicates dehydration, but can also be a sign of chronic heart failure, COPD, or true polycythemia.
Erythrocyte sedimentation rate (ESR)
This test is designed to assess how quickly blood divides into plasma and red blood cells. The test results are used to diagnose diseases associated with acute or chronic inflammation, including cancer, infections and autoimmune diseases. Infectious and inflammatory diseases, connective tissue diseases, cancer, myocardial infarction, anemia, burns, and trauma increase the ESR, while decreased ESR is usually caused by polycythemia and diseases associated with altered red blood cell shape.
How to prepare for a blood test
- One day before the appointed time of blood sample taking, to refrain from drinking alcohol.
- It is recommended to exclude taking medicines the day before the blood collection (requires a separate agreement with the doctor).
- 8 hours before the examination to refrain from eating, non-carbonated water is allowed.
- Half an hour before the blood test to avoid physical and emotional stress.
- Also half an hour before the examination exclude smoking.
