A full blood count consists of a small blood count and a so-called differential blood count. As a rule, a small blood count is made first, which gives the doctor treating you information about the number of individual blood cells .
If abnormalities are found here, the doctor usually orders another blood count, the so-called complete blood count. A full blood count includes a so-called differential blood count in addition to the small blood count. Here, the different types of white blood cells (leukocytes) are distinguished and their quantity and arrangement is determined.
What you should know about the complete blood count:
- A full blood count consists of a small blood count and a so-called differential blood count
- The differential blood count includes the precise examination of the individual cell types under the white blood cells (leukocytes)
- The complete blood count can be created automatically or analogously. In the case of analog creation, a specialist determines the values “by hand” under the microscope
- Dangerous pathogens such as malaria or HIV can also be identified with the help of a complete blood count
- Furthermore, there are other blood tests for almost all medical disciplines that provide different, even more detailed values
What is a complete blood count?
In addition to the standardized counting of the individual blood components in the small blood count, a full blood count includes an exact determination of the different leukocytes (white blood cells). Above all, if the doctor treating you suspects a chronic or acute infection, he will order a complete blood count.
The individual blood values that are determined in a complete blood count are:
Small blood count + differential blood count = full blood count
Blood count table with the normal values
| normal values | explanation of the values | values in women | values in men |
| erythrocytes | erythrocyte count | from 3.9 to 5.3 million/ µl | from 4.3 – 5.7 million/ µl |
| leukocytes | leukocyte count | from 3800 to 10500 µl | from 3800 to 10500 µl |
| granulocytes | |||
| stabkernige Neutrophile | 3 bis 5% | 3 bis 5% | |
| segmented neutrophils | 54 bis 62% | 54 bis 62% | |
| Eosinophile | 1 bis 4% | 1 bis 4% | |
| monocytes | 3 bis 8% | 3 bis 8% | |
| lymphocytes | 25 bis 45% | 25 bis 45% | |
| platelets | platelet count | from 140,000 to 345,000 µl | from 140,000 to 345,000 µl |
| Hkt | hematocrit | from 37 to 48% | from 40 to 52% |
| Hb | concentration of hemoglobin | 12 – 16 g/dl | 13,5 – 17 g/dl |
| MCH | amount of hemoglobin | from 28 to 34 pg | from 28 to 34 pg |
| MCHC | average hemoglobin concentration | from 33 – 35 g/dl | from 33 to 36 g/dl |
| MCV | average erythrocyte volume | from 85 – 95 fl | from 85 – 95 fl |
| g = grams | µl = microliter = 10-6 = 1 millionth of a liter | dl = deciliter (100 milliliters) Control values Dr.H.Stephans, 04/28/2018 www.blutwert.info |
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The individual blood values that are determined in a complete blood count are:
The small blood picture with the values:
- Number of erythrocytes (red blood cells)
- Hemoglobin (blood pigment)
- Percentage of cell volume (hematocrit)
- the MCV value (cell volume of red blood cells)
- the MCH value (concentration of hemoglobin in a red blood cell)
- the MCHC value (concentration of hemoglobin in all erythrocytes)
- Number of thrombocytes (blood platelets)
- Number of leukocytes (white blood cells)
as well as a differential blood count with the values:
- Number of different types of leukocytes
– monocytes
– lymphocytes
– eosinophilic granulocytes
– basophilic granulocytes
– segmented granulocytes
– rod-nucleated granulocytes
The different types of leukocytes are determined quantitatively here. This means that the values provide information about the concentration of the individual cell types in the whole blood. The so-called morphology of the cells is also determined, which means checking the cell composition. Colloquially, this process could also be referred to as quality control.
When is a complete blood count necessary and how is it done?
A small blood count is part of the routine examinations and is part of the general preventive care. A complete blood count, on the other hand, is usually created when there is a suspicion of an acute or chronic infection.
For a full blood count, the patient must be fasting at the time the blood is taken. This means that by 8:00 p.m. the evening before, he had stopped eating solid food and then only drank water and unsweetened tea. The cup of coffee should only be drunk after the blood has been taken.
The blood sample taken by the doctor treating you is usually early in the morning, so that you can have breakfast immediately after the blood sample is taken. The blood sample taken is then sent to a laboratory. While just a few years ago all cell types had to be counted by hand under a microscope, this task is now performed by complex machines.
The values of the full blood count are communicated to the treating doctor with the so-called laboratory findings.
However, the doctor treating you can also request a so-called analogue blood count. Then the corresponding values are still determined manually under the microscope by a specialist.
If these values are available, the treating doctor can discuss the values with his patient, make a diagnosis and rule it out or, under certain circumstances, order further examinations.
Changes in the complete blood count – what now?
In addition to diseases of the blood itself, changes and diseases in organs such as the liver or kidneys can also lead to deviating values in the complete blood count. The different cell types that are created in the differential blood count react differently to a variety of diseases.
Leukocyte count – full blood count:
If the number of leukocytes is too high, doctors speak of leukocythosis. Especially with bacterial infections, the number of leukocytes increases significantly. Other causes can be:
- Stress
- inflammation
- poisoning
- allergies
- regular use of certain medications
- Cancers that are already advanced
- blood cancer ( leukemia )
- states of shock
- Metabolic diseases (e.g. gout)
If there are not enough leukocytes, this symptom is called leukopenia . Leukopenia occurs primarily in people who are being treated with chemotherapy , have bone marrow damage, or have a viral infection. Certain diseases can also cause leukopenia, since leukocytes are increasingly broken down here.
Number of neutrophil granulocytes:
Neutrophil granulocytes are the most common of the white blood cells in the blood. They are kept “on demand” in the body, for example in the spleen, and released in large quantities when required, for example in the event of an infection with bacteria.
If this value is elevated, there is every indication that such a release has taken place and that an infection is probably present. Neutrophilic granulocytes eat cell debris and dead parasites and bacteria. A buildup of neutrophils, dead cells, and lymph fluid is popularly known as pus.
Number of basophil granulocytes:
In a healthy person, basophilic granulocytes make up less than 1 percent of the blood, as they are mainly found in the body’s tissues and lymphatic system. They play a role in infections and allergic reactions in particular. However, slight increases in this value also occur with increased blood lipid levels, for example when a person is suffering from diabetes.
changed values
If values in the full blood count are abnormal, the doctor treating you will seek a conversation with the person concerned and answer all questions here and, under certain circumstances, order further examinations.
A complete blood count can also be helpful in detecting dangerous pathogens such as malaria or HIV and making early treatment possible.
In almost all medical fields, there are also other, more specific blood tests that provide additional values to secure diagnoses.
Sources
Marlies Michl: BASICS Hematology. 4th edition. Munich 2016: Elsevier/Urban & Fischer-Verlag. ISBN-10: 3437421697.
Dr. Harald Stephan, www.grossesblutbild.de/grosses-blutbild.html
