Hematology

Hematology - analyses

Complete Blood analysis
Erythrocytes
Hemoglobin
Hematocrit

What is Erythrocyte sedimentation?
How is Erythrocyte sedimentation rate determined?

HEMATOLOGICAL ANALYSESCOMPLETE BLOOD ANALYSIS

Hematology (from Greek haima = blood, logos = science) deals with the study of blood properties in both healthy individuals and patients suffering from various diseases. The most common hematological analyses that are part of the daily laboratory routine are complete blood count and erythrocyte sedimentation rate (ESR).

Complete blood count (CBC) provides us with the following information: the value of hemoglobin and hematocrit in the blood, the number of erythrocytes, leukocytes, and platelets along with accompanying erythrocyte indices (MCV; MCH; MCHC; RDW) and platelet indices (PDW and MPV), as well as the differentiation of the total number of leukocytes into leukocyte subtypes – differential blood count (DIFF).
Complete blood count is performed as a basic and integral part of routine control or, in acute conditions, as an adjunct diagnostic tool to establish a timely and accurate diagnosis by a physician. The obtained results can provide us with information about the general condition of the organism, existing anemia, acute viral or bacterial infection, present allergies, presence of parasites, as well as possible intoxication (poisoning). It is recommended that, if there are no indications, a complete blood count should be checked at least once a year. Venous or capillary blood samples are used for blood analysis, and the obtained results are interpreted by a physician in accordance with the patient’s clinical picture.

HEMATOLOGICAL ANALYSESErythrocytes

Erythrocytes (RBCs) are red blood cells and represent the most numerous type of cells in the body. Their primary role in the body is the transport of gases – oxygen from the lungs to tissues and carbon dioxide in the opposite direction. In addition, erythrocytes are responsible for most of the blood buffering capacity because they contain the enzyme carbonic anhydrase, a catalyst for the reaction of water and carbon dioxide. However, the number of erythrocytes alone does not have great diagnostic value because even minimal changes in plasma volume (dehydration, diarrhea, etc.) alter their count. The number of erythrocytes is always observed together with hemoglobin and hematocrit levels. Reference values depend on gender and age.

HEMATOLOGICAL ANALYSISHemoglobin

Hemoglobin (HGB) is a protein found in erythrocytes (red blood cells). Its role is to transport oxygen, necessary for the smooth functioning of cells, from the lungs to tissues and carbon dioxide from tissues back to the lungs. The normal concentration of hemoglobin depends on gender and age. The value of hemoglobin may be decreased in certain specific conditions (menstrual cycle in women, certain disorders in erythrocyte hematopoiesis, or anemic conditions). Increased hemoglobin value can be encountered in states of hemoconcentration and polycythemia (polycythemia is a condition characterized by an increase in the number of erythrocytes or an increase in hematocrit above normal values, of unknown cause).

HEMATOLOGICAL ANALYSISHematocrit

Hematocrit (HCT) is the percentage by volume of erythrocytes in the whole blood, i.e., the percentage of blood composed of erythrocytes (red blood cells). Expected hematocrit values are around 48% for men and 38% for women. A decreased hematocrit value may indicate a deficiency of erythrocytes or anemia due to iron deficiency (in this case, erythrocytes have a smaller volume due to the lack of hemoglobin, for whose formation iron is necessary), and the number of erythrocytes itself does not necessarily have to be reduced. An increased hematocrit value may indicate an elevated risk of blood clots formation that can lead to a heart attack or stroke due to clot formation as a consequence of thicker blood. It may occur in cases of dehydration, bone marrow disorders, hypoxia, etc.

HEMATOLOGICAL ANALYSISThe average hemoglobin value in erythrocytes (MCH)

The average hemoglobin value in erythrocytes - (Eng. mean corpuscular hemoglobin) is a derived value. It represents the ratio of hemoglobin concentration to the number of erythrocytes in the blood. Generally, the MCH value parallels changes in the MCV index. Reference values range from 26–34 pg.

HEMATOLOGICAL ANALYSISAverage Concentration of Hemoglobin in Erythrocyte (MCHC)

The average concentration of hemoglobin in erythrocytes - (Eng. mean corpuscular hemoglobin concentration MCHC) is a measure of the amount of hemoglobin found in an average erythrocyte, given to the size of the erythrocyte. It does not depend on gender or age. The MCHC value can be decreased but not increased, as it is physiologically impossible for erythrocyte to contain more than 370 g/L of hemoglobin.

HEMATOLOGICAL ANALYSISRed Cell Distribution Width (RDW)

Red cell distribution width refers to the variation in the size of erythrocytes, known as anisocytosis. RDW is a measure of this variation. Any condition that leads to a significant difference in the size of erythrocytes results in an elevated RDW index.

HEMATOLOGICAL ANALYSISAverage erythrocyte volume (MCV)

Average erythrocyte volume (Mean corpuscular volume – MCV) is a measure of the volume of an average erythrocyte. Along with other erythrocyte indices, it provides useful information related to anemia. Based on the MCV value, anemia can be classified as microcytic, normocytic, or macrocytic:

Microcytosis: Erythrocytes with reduced volume (<80 fL)
Normocytosis: Erythrocytes with normal volume (80–96 fL)
Macrocytosis: Erythrocytes with increased volume (>96 fL)

The determination of MCV value can be affected by a significantly increased white blood cell count as well as erythrocyte agglutination. Falsely increased values are found in diabetic ketoacidosis due to plasma hyperosmolarity. The MCV index value can be increased even without the presence of anemia. In such cases, it may indicate:

Alcoholism
Drug-induced macrocytosis
Megaloblastic anemia

HEMATOLOGICAL ANALYSISLeukocytes

Leukocytes (WBCs) are white blood cells and make up about 1% of all blood cells. Their primary role is to protect and defend the body against infections. There are five main types of leukocytes, each with different roles:

Lymphocytes: Responsible for producing antibodies needed to defend the body against bacteria, viruses, and other threats.
Neutrophils: Destroy bacteria and fungi.
Basophils: Serve as a warning signal for infections by secreting certain substances into the bloodstream, primarily fighting against allergies.
Eosinophils: Indicate an allergic reaction and are responsible for destroying parasites and cancer cells.
Monocytes: Attack and break down viruses and bacterial cells.

An elevated level of leukocytes is called leukocytosis and can be seen in the following conditions: bacterial infections, use of certain medications (e.g., corticosteroids), pregnancy, smoking, obesity, genetic conditions or diseases, injuries, immunosuppression, allergic reactions, etc. Any number of leukocytes >11 × 10^9/L is considered leukocytosis. Leukocytosis itself has no major clinical significance unless the specific type of leukocyte in excess is identified. Therefore, the leukocyte formula is crucial for a complete blood count. Based on results obtained from an automatic hematology counter or a peripheral blood smear examination, we can distinguish:

Neutrophilia
Lymphocytosis
Eosinophilia
Basophilia
Monocytosis

HEMATOLOGICAL ANALYSISPlatelets (PLT)

Platelets – (Eng. Platelets PLT) are blood cells that play an important role in stopping bleeding by forming a platelet plug. The normal platelet count ranges from 150 to 400 billion per liter of blood. A reduced number of platelets is called thrombocytopenia, while an increased platelet count is called thrombocytosis.

HEMATOLOGICAL ANALYSISAverage Platelet Volume (MPV)

Average Platelet Volume - (Eng. Mean platelet volume MPV) is a platelet index that indicates the size of platelets, which is crucial for their functionality. Decreased MPV values indicate an increased tendency to bleeding. MPV does not depend on gender or age; expected values range from 7.0 to 11.0 fL.

HEMATOLOGICAL ANALYSISThrombocrit (PDW)

Thrombocrit (Platelet distribution width PDW) represents the distribution of platelets by volume. The number of platelets, along with PDW and MPV indexes provide important information on the blood coagulation process.

HEMATOLOGICAL ANALYSISWHAT IS ERYTHROCYTE SEDIMENTATION RATE (ESR) AND WHY IS IT MEASURED?

One of the most common analyses included in annual (or more frequent) check-ups is the erythrocyte sedimentation rate (ESR). The results obtained provide information about potential inflammation in the patient’s body. If the sedimentation rate is increased, it is considered indicative of either chronic or acute inflammation. Therefore, this parameter is determined as one of the inflammatory markers. Unfortunately, it is not sufficiently specific, meaning it does not provide information about the location of inflammation. Similarly, it is not sensitive enough, so we cannot be certain there is no inflammation if the sedimentation rate result falls within the expected values for healthy individuals.

HEMATOLOGICAL ANALYSISHOW IS ERYTHROCYTE SEDIMENTATION RATE DETERMINED?

The determination of erythrocyte sedimentation rate is carried out from blood, in a specific test tube containing a certain type of anticoagulant. The results are read after 1 hour using the original Westergren method and expressed in mm (height). Nowadays, the modified Westergren method is increasingly being used, according to which the reading is done after 30 minutes, and the test tubes used for this purpose are adapted to the modification itself.

HEMATOLOGICAL ANALYSISWHEN IS ERYTHROCYTE SEDIMENTATION RATE ANALYSIS DONE?

The determination of erythrocyte sedimentation rate is done:

As an integral part of routine medical check-ups.
As one of the parameters to assess inflammation, along with:
- Complete blood count with leukocyte formula.
- CRP (C-reactive protein) levels.
- Optionally, D-dimer levels.
According to the doctor’s order, especially if you are experiencing symptoms of inflammatory conditions such as fever, weight loss, loss of appetite, headaches, malaise, anemia, etc. It is not recommended to determine the erythrocyte sedimentation rate during pregnancy due to potentially increased values that may be attributed to physiological changes.