Leukopenia - is a reduced white blood cells (WBC) count otherwise below the lower limit of normal (usually below 3.5 - 4 G/l, depending on the norms of a particular laboratory). The cause of leukopenia can be hematological diseases such as leukemia, myelodysplastic syndromes, or certain types of lymphoma, but also non-hematological diseases, including autoimmune diseases, nutritional deficiencies, chronic infections or commonly used medications. It is not always associated with a disease state, but this can only be determined after ruling out a number of conditions leading to its development. Leukopenia may or may not lead to an increased risk of infection.

Leukocytosis - is an increased number of white blood cells above a WBC level of >10 G/L. It most often occurs in the course of bacterial or other infections, but a suddenly rising leukocyte count or persistently elevated leukocytes over time requires an in-depth hematological diagnosis. Leukocytosis occurs in the course of leukemia, lymphoma or myeloproliferative neoplasms, among others.

Anemia is a situation in which we observe a reduced hemoglobin (Hb) level and the total number of red blood cells (RBC, red blood cells). Norms for Hb levels vary - in women, anemia is diagnosed when Hb<12 g/dl (7.4 mmol/l) and in men <13 g/dl (7.7 mmol/l); note that the norm for the laboratory where the test was performed should be taken into account. Initial symptoms are quite nonspecific, including weakness, palpitations, difficulty concentrating, dizziness, pale skin, lethargy, cracking of the corners of the mouth, increased brittleness of the nails or hair loss. A number of genetic (so-called congenital) as well as acquired diseases can lead to anemia. Acquired causes include deficiencies of iron, vitamin B12, autoimmune diseases such as celiac disease, chronic diseases (i.e. kidney disease, inflammatory diseases), solid tumors and hematological diseases. Among anemias, there are:

1. Iron deficiency anemia is the most common anemia, and is especially more commonly diagnosed in women. Common causes include increased monthly bleeding, gastrointestinal diseases leading to gastrointestinal bleeding or impaired iron absorption, or an ill-balanced diet. An increased need for iron occurs in pregnant women.
2. Vitamin B12 deficiency anemia - its most common cause is an autoimmune disease leading to antibodies forming and vitamin B12 malabsorption. Such a state is referred to as Addison-Biermer disease. In addition to the typical symptoms of anemia, neurological symptoms, i.e. numbness or prickling of the fingertips, numbness and weakness of the limbs, gait disturbances, can be observed in cases of vitamin B12 deficiency.
3. Folic acid deficiency anemia - is associated with a deficiency of folic acid most often in the course of dietary errors (eating too little vegetables or too much alcohol), but can also accompany other diseases of the gastrointestinal tract, or as a result of the use of drugs. The symptoms of this anemia are similar to those associated with vitamin B12 deficiency, but no neurological symptoms are found. Folic acid deficiency in pregnant women can cause abnormalities in the development of the nervous system in the fetus.
4. Hemolytic anemias - can be both congenital and acquired diseases. This is a very diverse group of diseases that lead to excessive destruction of red blood cells in the body due to various pathological mechanisms. Additional symptoms that can be observed in this group of anemias are yellowing of the body's coats (jaundice), enlargement of the liver (hepatomegaly), spleen (splenomegaly) and in some types of anemia, there is an increased incidence of gallstones.

Polycythaemia (polyglobulia) - is defined as a condition when blood count shows an elevated level of hemoglobin (Hb >16.5 g/dl in women, Hb >18.5 g/dl in men). Hypercoagulability can occur in the course of malignant disease of the bone marrow (mainly verrucous melanoma), but it can also be the result of other diseases (then we speak of secondary hypercoagulability), i.e., lung or heart disease, or compulsive smoking, consumption of drugs. Hypercoagulability, like hypercoagulability, is associated with an increased risk of thromboembolic complications. Symptoms of hypercoagulability can include itchy skin after a hot bath, a bluish-red facial coloration, and in the advanced form, weakness, and poor exercise tolerance. Elevated arterial blood pressure may also be one of the symptoms.

Thrombocytopenia - is a reduction in platelets below normal values (PLT <150 G/l). This condition can be led by disorders of platelet production (so-called central thrombocytopenia in the course of myelodysplastic syndromes, lymphoma, leukemia or bone marrow fibrosis) and their excessive destruction (so-called peripheral thrombocytopenia in the course of autoimmune diseases, infections or drug use). Platelets are responsible for the clotting process; hence their deficiency can lead to prolonged bleeding, a tendency to bruising or the appearance of petechiae on the skin or mucous membranes.

Thrombocytemia - is an increased platelet count above the upper limit of normal (PLT >450 G/l) leading to an increased risk of thromboembolic complications such as pulmonary embolism or deep vein embolism. The causes of thrombocytemia vary and may be related to iron deficiency, hematologic diseases (myeloproliferative neoplasms), inflammation and infections.