Leukocyte formula

which quantifies the number of white blood cells in one cubic millimeter of blood, also expressing the quantitative and percentage ratio of the various types of white blood cells.

White blood cells - also known as leukocytes (hence the term leukocyte formula) or WBC (White Blood Cells) - are the defense cells of our organism.

Five types are known (neutrophils, eosinophils, basophils, lymphocytes, monocytes), each of which with some specific functions and with a relatively stable percentage ratio from individual to individual.

Precisely quantifying the white blood cell subpopulation using the leukocyte formula helps doctors assess the patient's health status and make a diagnosis.

Also known as differential leukocyte count, the leukocyte formula is performed on a blood sample taken from the patient, who must be in baseline condition after fasting for approximately 10 hours. Physical stresses and important stresses before the exam can in fact alter the values.
The leukocyte formula is normally inserted into the blood count, a "standard" blood test that also includes the red blood cell and platelet count, as well as additional and important blood parameters.

The count can be carried out automatically by electronic counters, or by observing a drop of blood streaked on a slide under an optical microscope (see blood smear).

and chemicals, capable of irreversibly damaging the membranes of pathogenic microorganisms

PERCENTAGE NORMAL VALUES ABSOLUTE VALUES PER CUBE MILLIMETER 40-80% 3.000 - 7.000 / mmc

LYMPHOCYTES

In reality, lymphocytes include several subtypes: the main ones are B, T and Natural Killer lymphocytes. These subpopulations have different functions: the B lymphocytes produce antibodies, molecules important in the defense of the organism from infections; the T lymphocytes do not produce antibodies but process other molecules important in the defense against infections, especially viral. They are also able to specifically recognize foreign cells and play an essential role in the defense of the organism from tumors and in the rejection of transplants. Natural Killer (NK) cells are similar to T lymphocytes.

PERCENTAGE NORMAL VALUES ABSOLUTE VALUES PER CUBE MILLIMETER 20-40% 1,500 - 3,000 / mmc

MONOCYTES OR MACROPHAGES

They are important in defending the body from certain types of bacteria, such as the one that causes tuberculosis. They engulf and digest foreign elements and damaged cells.

PERCENTAGE NORMAL VALUES ABSOLUTE VALUES PER CUBE MILLIMETER 2-8% 100 - 700 / mmc

EOSYOPHILES

Their main function is the defense of the organism from certain types of parasites. Eosinophils also increase in allergic diseases (bronchial asthma, allergic rhinitis, urticaria, etc.) and can be responsible for some symptoms characteristic of these diseases.

PERCENTAGE NORMAL VALUES ABSOLUTE VALUES PER CUBE MILLIMETER 1-4% 100-400 / mmc

BASOPHILES

Their function is not very well known. They too increase in allergies: they contain histamine which, if released in excess in the blood and tissues, causes annoying symptoms (such as itching or the appearance of skin wheals), to combat which drugs called antihistamines are often used.

PERCENTAGE NORMAL VALUES ABSOLUTE VALUES PER CUBE MILLIMETER 1% 20-50 / mmc

TOTAL NUMBER OF LEUCOCYTES

PERCENTAGE NORMAL VALUES ABSOLUTE VALUES PER CUBE MILLIMETER 100% 4,000 - 10,500 / mmc

• in green the group of granulocytes (neutrophils, basophils and eosinophils)

PLEASE NOTE: between the two values ​​(percentage and absolute) it is more important to consider the absolute one; in fact, evaluating the percentage value alone runs the risk of misinterpreting the outcome of the leukocyte count. For example, the latter could be excessive or too low even when it is absolutely normal in absolute terms; this can happen due to the simultaneous increase or reduction of another category of leukocytes, with a variation in the absolute number of white blood cells.

Acute infections (bacterial and fungal)

Acute stress

Eclampsia

Gout
Myeloid leukemias

Rheumatoid arthritis

Rheumatic fever
Trauma
Tumors
Sterile inflammatory diseases / tissue necrosis (Burns, myocardial infarction)

Thyroiditis

Anxiety and severe physical activity

Collagen diseases

Acute renal failure

Ketoacidosis

Splenectomy

Congenital neutropenia
Lymphomas
Diseases of the bone marrow
Severe infections
Aplastic anemia

Flu or other viral infections
Anaphylactic shock
Taking certain medications (eg methotrexate) and chemotherapy

Radiation therapy or exposure to ionizing radiation

LYMPHOCYTES

CAUSES HIGH VALUES = Lymphocytosis CAUSES LOW VALUES = Lymphocytopenia

Lymphatic leukemias
Chronic bacterial infections

Infectious mononucleosis and other viral diseases (mumps, measles, flu, chicken pox, herpes simplex, viral hepatitis)
Rheumatic diseases

Multiple myeloma
Drug addiction
Inflammation

Congenital deficiencies
AIDS (end-stage) and immune system diseases (lupus)

Severe renal failure with uremia

Chemotherapy

Radiation therapy or exposure to ionizing radiation

Chronic diseases (sarcoidosis, lupus, multiple sclerosis, myasthenia gravis, Guillain Barré syndrome)

MONOCYTES OR MACROPHAGES

CAUSES HIGH VALUES = Monocytosis CAUSES LOW VALUES = Monocytopenia

Leukemia
Myeloma
Infectious mononucleosis
Cirrhosis of the liver

Chronic inflammatory diseases

Tuberculosis, syphilis, brucellosis, listeriosis

Chronic infections

Bacterial endocarditis

Leukemia
Myeloma

Chemotherapy and immunosuppressive treatments

Aplastic anemia

EOSYOPHILES

CAUSES HIGH VALUES = Eosinophilia CAUSES LOW VALUES = Eosinophilopenia Allergies (bronchial asthma, allergic rhinitis, urticaria, etc.)
Hypersensitivity to drugs
Autoimmune Diseases
Parasitic diseases
Scarlet fever

Hypoglycemia
Prolonged exposure to sunlight
Shock
Stress (including from trauma and surgery)
Chronic renal failure
Use of cortisone

Cushing's syndrome

BASOPHILES

CAUSES HIGH VALUES = Basophilia CAUSES LOW VALUES = Basophylopenia Some types of Leukemia
Gangrene
Chronic infections
Allergic reactions to food (IgE mediated)
Parasitosis
Following radiotherapy

Pregnancy

Hyperthyroidism

Acute stress and hypercortisolism

Often associated with eosinophilopenia

Some drugs can also alter the values ​​of the leukocyte formula.
Prolonged use of steroids and long-term exposure to toxic elements (such as caustic soda or insecticides) may increase the risk of having an abnormal result in the differential white blood cell count.

complete (complete blood count), where we will also proceed with the analysis of the red blood cell and platelet counts, the calculation of the hematocrit and the corpuscular indices. The patient is then taken a blood sample from a vein in the arm, usually in the morning and on an empty stomach.
Counting can be done automatically by electronic counters or by observation under an optical microscope (blood smear).