Blood Picture: Treatment, Effect & Risks

Blood count represents one of the most commonly used diagnostic methods today, as many diseases are associated with characteristic blood count changes. Thus, it provides a rapid assessment of health status with comparatively little effort on the part of the patient and practitioner.

What is a blood count?

A blood count represents one of the most commonly used diagnostic methods today, as many diseases are associated with characteristic blood count changes. A blood count is performed as follows: First, blood must be drawn from the patient. Usually, a vein in the bend of the elbow is used for this purpose. It is not necessary for the patient to remain fasting for the blood draw, but he or she should avoid fatty foods in the last few hours before the draw. Otherwise, fat particles, the so-called chylomicrons, may be present in the blood sample and lead to incorrect readings. Since the blood or plasma concentrations of some substances fluctuate when the patient is standing, it is advisable to take the sample in a sitting or lying position. It should also be noted that some measured values fluctuate during the course of the day. For this reason, follow-up tests in particular should always be performed at the same time of day. In the laboratory, the relevant parameters for the respective clinical question are determined with the aid of mechanical blood count analyzers. In some cases, a distinction is made between a large and a small blood count. For a small blood count, the erythrocyte, leukocyte and platelet counts, the hemoglobin concentration, the hematocrit value and the erythrocyte indices MCV, MCH and MCHC are determined. For a complete blood count, several other parameters are determined. Because modern blood count analyzers usually produce a complete blood count immediately, the differentiation into large and small is often no longer made.

Function, effect and goals

The values recorded for the blood count have different meanings. For example, erythrocytes, or red blood cells, are important for oxygen transport in the body. The standard value for the erythrocyte count is 4.0 to 5.5 for women and 4.6 to 6.0 for men. Numbers above or below these limits can have a variety of causes that must be detected, otherwise serious disturbances in the body’s oxygen supply can occur. Causes for an increase in the red blood cell count are usually a lack of fluids, a shortage of oxygen, or even stress. A reduced number is also known as anemia. In many cases it is an indication of iron deficiency, but it can also occur as a result of major blood losses. These blood losses are not always noticed by the patient, as they are not necessarily caused by an externally visible wound. Bleeding inside the body, such as in the intestines, can also be responsible for anemia. To further classify anemia, the parameters MCH, MCV and MCHC are used. This allows statements to be made about the quality of the erythrocytes. For this purpose, the hemoglobin content of a single erythrocyte, the volume as well as the proportion of hemoglobin in the total volume of red blood cells are considered. If these three values are within the norm, we speak of normocytic and normochromic anemia. In this case, the formation of new erythrocytes is too slow for the current demand. This is often caused by a high blood loss. Sometimes, however, the hormonal regulation of erythrocyte formation does not function correctly. If MCV, MCH and MCHC are reduced, this is a microcytic anemia. Almost always, this form is due to iron deficiency. Iron is important for the production of hemoglobin, the red blood pigment. Consequently, iron deficiency leads to the inability to produce enough hemoglobin. The erythrocytes are then not sufficiently loaded with it and are consequently too small. Erythrocyte formation also requires various substances as cofactors, first and foremost vitamin B12. If this vitamin is lacking, erythrocytes are produced that are too large and are also loaded with too much hemoglobin. Since a vitamin B12 deficiency can cause further damage, substitution can be initiated immediately if necessary on the basis of the blood count. Finally, the platelet and leukocyte counts are important measurements of the blood count. Thrombocytes are also known colloquially as “blood platelets“. They are important for blood clotting, for example after injuries.The leukocytes, also known as “white blood cells“, have a variety of tasks within the framework of the immune defense system. If leukocyte levels are significantly altered, further diagnostics must follow, as life-threatening diseases may also be the cause.

Risks, side effects, and hazards

Overall, the collection of a blood count is an inexpensive and easy-to-perform method to monitor a patient’s health or find the cause of symptoms. In addition, it takes only a short time to evaluate a blood sample. In most cases, results are available after just one day. For the patient, the blood sample is also taken with little effort, and undesirable effects are not to be expected. In addition to the blood count changes mentioned above, there are many other characteristic changes that can be used to identify diseases with a high degree of probability. Blood analysis can also be used to request values that go beyond the standard parameters, so that differentiated diagnostics are easily possible. For example, a precise hormone status can be recorded and effective treatment can be initiated on this basis. Likewise, adequate monitoring of the course of chronic diseases is possible via the blood count. In this case, too, it is possible to intervene if necessary in the event of changes and to adjust the treatment. All these advantages are responsible for the fact that the blood count plays a major role in diagnostics in almost all disciplines. It provides valuable information for further action with comparatively little effort.