Blood tests for pneumonia


In addition to physical complaints, pneumonia usually also leads to changes in blood values. By taking a blood sample from those affected, the blood can be examined for inflammation-specific signs in the laboratory and, if the infection values ​​are positive, the diagnosis of pneumonia can be supported.

This is what the blood values ​​look like in the case of pneumonia

Pneumonia usually changes certain blood values, including in particular white blood cells and CRP, the so-called C-reactive protein. The white blood cells, also called leukocytes, are part of the body's defense cells, so their function is to fight bacteria and other pathogens. The large group of leukocytes includes granulocytes, which are specifically responsible for the defense against bacteria, and lymphocytes, which play a major role in the defense against viruses.

In the context of pneumonia, their number increases accordingly, this is called in medical terminology Leukocytosis designated. In the case of a bacterial infection, those affected often show a large number of the aforementioned granulocytes, which, however, are often not yet fully developed and are still in different stages of development in the blood. This phenomenon is called left shift in medicine.

Furthermore, there is an increase in the C-reactive protein, also called CRP. It is a protein that occurs during inflammation. However, it is very unspecific and can occur more frequently in the context of many infections. Procalcitonin is also typical of bacterial pneumonia; this is increased in the course of the infection. In connection with pneumonia, procalcitonin is considered to be far more specific than CRP, since it increases in particular with bacterial infections, whereas CRP can appear with an increased value in the context of various diseases.

Furthermore, an increased sedimentation rate (ESR) can occur. Here, too, it is more a question of a non-specific value, which can also be changed in the context of anemia, for example.

Read more on this topic at:

  • Inflammation in the blood
  • Blood count
  • Laboratory values
  • Diagnosis of pneumonia


CRP is the abbreviation for C-reactive protein. It is a protein that occurs more frequently in the blood when there is an infection. If there is inflammation or tissue breakdown, an increased concentration of CRP in the blood can occur. An increased CRP value is to be expected in the context of pneumonia. However, since this is a very unspecific value, pneumonia cannot be explicitly assumed if a CRP increase occurs on its own, rather it indicates that “something is going on” in the body. The level of the value of CRP in turn can indicate the severity of a disease. Particularly high values ​​are therefore to be viewed as an indication of a serious infection or illness.

Read more on this topic at: CRP value

Leukocytes / white blood cells

The leukocytes are also known as white blood cells. They are a large group of blood cells that specialize in defending against pathogens such as bacteria, viruses and fungi. The leukocytes are subdivided into lymphocytes and granulocytes, among other things. In the course of pneumonia, there is an increase in white blood cells or granulocytes because their area of ​​responsibility is primarily to fight bacteria. The granulocytes can then be found in increased concentrations in the blood values.

In medical terminology, an increased amount of white blood cells is called lymphocytosis. Under this abnormally increased concentration of granulocytes it is also noticeable that these are predominantly in immature states. There is also a medical term for this that describes this circumstance - namely the left shift. In summary, the typical, if not disease-specific, features of pneumonia include an increase in white blood cells or their subgroup of not yet mature blood cells, the so-called granulocytes.

Read more on this topic at: Lymphocytes