Platelet norms, Fonio analysis, methods of normalization

Blood test

The general analysis of blood includes the study of the quantitative composition of blood cells: erythrocytes, leukocytes and platelets.

Composition of blood

The laboratories use automatic hematological counters, but microscopic analysis methods remain the most informative and accurate. One of such methods is a phonio smear microscopy for counting the number of platelets.

Smear microscopy is used in those cases when the results of studies of automatic counting by hemoanalysers deviate significantly from the norm. Platelets by Fonio are counted according to a formula tied to the value of the absolute number of red blood cells in the blood. Therefore, the technique is part of a general blood test and is performed after an automatic count of the number of other blood cells (erythrocytes).


  • Platelets
  • Method for calculating platelets by Fonio
    • Performing an Analysis
    • Calculation of platelets
  • Reliability of results
  • Decoding results, reasons for deviations
    • High platelets
    • Low platelets
  • How to normalize platelet counts


Platelets are non-nuclear cells formed from bone marrow megakaryocytes. After maturing and entering the blood, the cell lives 5-7 days. Old cells are disposed of by the liver and spleen. The aging process in these cells is particularly pronounced.

Platelets, like other blood cells, are divided into young, mature and old. Normally, the blood contains at least 95% of mature cells. The release into the blood of immature cells can be caused by an irritant factor (multiple vascular injuries). In the blood can be found and degenerative, old cells, which indicates the pathology of the process of maturation and utilization.

Platelets are the main participants in the processes of thrombus formation. However, by isolating specific enzymes, they stimulate cell division and tissue regeneration, regulate the level of permeability of cell membranes, maintain the elasticity of the walls of the vessels.

By their number, you can determine the state of health of the cardiovascular system. Elevated amount is called thrombocytosis, lowered - thrombocytopenia.

Cell functions

Platelets are well stained with dyes. Depending on the degree of maturity, cells are stained with different intensities, which simplifies the differential diagnosis of their morphological composition.

Method for calculating platelets by Fonio

Cells are counted in different ways. The Goriaev camera and the Fonio method are fundamentally similar and are the most common. The essence of the Fonio method is the parallel counting of colored cells of erythrocytes and platelets in the fields of the microscope grid. In the Goriaev chamber, this grid is applied by a laser to the glass itself.

Calculation of platelets by Fonio is performed using inexpensive reagents:

  • As the coagulant used 14% solution of magnesium sulfate or 6% solution of sodium ethylenediaminetetraacetate (EDTA);
  • To fix the smear use Leishman's solution (a solution of eosin-methylene blue in methanol).
  • Eosin stain Gypsum for painting according to Romanovsky.

The method of calculating platelets by the method of Fonio is popular not only because of its simplicity and low cost. Unlike the counting of platelets in Goryaev's chamber, the microscopy of the Fonio smear can be performed a few hours or days after the analysis is submitted. Laboratories, littered with current applications, this allows you to reduce the peak loads associated with the morning rush of patients.

In addition, the possibility of repeated microscopy in a few days will allow you to compare the readings or clarify the result of the count.

Performing an Analysis

For the analysis, capillary blood (from the finger bundle) is used.

After the puncture, the first drop is not used, it is removed with cotton wool. A second drop is taken for the smear. Usually, the coagulant is added to a drop of blood and immediately put the sample on the glass. But a lab technician can mix blood with a coagulant in a test tube.

The smears are fixed and stained using Pappenheim's method. When applied to a prepared blood smear a few drops of fixative solution, the cells are glued to the glass. Hematologic fixatives are able to stain cells, which speeds up the process of smear preparation.

Then, a few drops of Giemsa-Romanovsky's paint are applied to the smear and held for 2-3 hours. (using magnesia) or 30-45 minutes. (using ETA as a coagulant). As a result, the blood cells are stained and well visible for manual counting.

After washing, the smear is dried in a drying cabinet and proceeds to the study with a microscope equipped with an immersion objective and segmented eyepieces.

Calculation of platelets

The mesh applied to the eyepieces facilitates the counting of platelets in the blood smear. The laboratory assistant counts the number of cellular elements in the sectors of this grid.

Smear under the microscope

Parallel counting of the number of erythrocytes and platelets starts from one sector, and moving the eyepiece, they move on to the next sector. Counting is completed when the number of red blood cells reaches 1000.


Important! The error of the method is due to the fact that the counts take into account only the accumulations of these cells. Separate located single cells are not considered.


After the number of platelets, attached to 1000 cells of erythrocytes, is obtained, the absolute number of cells per unit volume of blood is calculated. To do this, you need the absolute value of the red blood cells of this patient, obtained in an automatic analyzer.

The calculation is carried out according to the following formula: the absolute value of the erythrocytes is divided by 1000 and multiplied by the number of platelets counted for microscopy:

where T is the number of counted platelets, E is the absolute number of erythrocytes.

Reliability of results

The poor quality of equipment and unclear compliance with the research method can affect the reliability of the result. Reasons for getting garbled data:

  • Use of substandard chemicals;
  • Improper preparation of solutions;
  • Non-observance of the timing of staining;
  • Incorrect drying chamber mode.

In the conditions of mass microscopy, the proper organization of work, marking and storage of samples is of particular importance.

Obtaining objective results depends not only on the correct fulfillment of all the requirements of the technique by the laboratory assistant, but also on the patient himself. He must responsibly approach the examination procedure and prepare for the analysis:

  • Blood sampling is performed on an empty stomach, so the patient must refuse to eat 8 hours before the visit to the laboratory.
  • If the patient's lifestyle or working conditions are associated with persistent physical stress, it is recommended that they be limited 2 days before the analysis.
  • Fans of alcohol should remember that taking ethyl alcohol provokes a multiple rise in platelets.
  • Emotional stresses also have a negative effect on the picture of blood, so a few days before the delivery of tests should be conducted in a calm environment.

Descriptions of some drugs (heparin, prostaglandin, adenosine) contain information that the drug can temporarily affect the composition of the blood. The patient must necessarily inform the doctor of any medications taken. The doctor will assess the probability of distortion of the results of the analysis and take a weighted decision on the temporary cancellation of this tool.

Decoding results, reasons for deviations

In a standard laboratory form, platelets are designated PLT. The unit in which the results are presented are thousands of units per microliter. Usually in laboratory forms for comparison, the norm is indicated.

Table of normal blood composition

The blood platelet count for men is different from the norm for women. It depends on the age of the person.

  • The norm for men is 200-400 thousand / microliter;
  • For women - from 180 to 320 thousand / microliter.

Norm for children:

  • In newborns up to 2 weeks - from 100 to 420 thousand / microliter;
  • In children up to a year - from 150 to 350 thousand / microliter;
  • In children under 5 years - 180-380 thousand / microliter;
  • In children under 7 years - from 180 to 150 thousand / microliter.

During the period of menstruation, there is a normal (physiological) decrease in cells (75-200 thousand / μl). Two-fold reduction in the number of platelets is associated with the need for rejection of the uterine epithelium. Reduction of platelets in pregnant women (100-300 thousand / μL) is also considered normal.

During menstruation, taking an analysis for platelets is not recommended.

High platelets

Thrombocytosis, caused by the pathology of stem cells in the bone marrow, is called primary.

Physiological elevation of platelets as a reaction of the body to trauma, alcohol consumption, infection or poisoning is called secondary. The mechanism of this reaction is associated with an increased release of thrombopoietin, which stimulates the division and growth of platelets in the bone marrow.

Thrombocytosis can occur as a result of such diseases:

  • Tuberculosis;
  • Myeloid leukemia;
  • Anemia;
  • Arthritis;
  • Erythrocytosis;
  • Lymphogranulomatosis;
  • Acute infections;
  • Cancer of the liver, kidneys.

Poisoning, stress and intense physical activity can cause an increase in the number of platelets.


Important! With abundant blood loss on the background of a decrease in blood volume, the platelet count decreases only in the first hours, and after a few hours the level may increase several times.


Low platelets

The cause of thrombocytopenia is often uncontrolled self-medication drugs, the side effect of which is the development of thrombocytopenia.

The cause of thrombocytopenia can be such diseases:

  • Diseases of the liver (hepatitis, cirrhosis);
  • Dysfunction of the thyroid gland (hyperthyroidism, hypothyroidism);
  • Specific types of leukemia;
  • Megaloblastic anemia;
  • Alcoholism.

With prolonged thrombocytopenia, the walls of the vessels become brittle, minor cuts and vascular damage lead to prolonged bleeding.

To clarify the cause of low platelets and the appointment of therapy, the patient will have to undergo many additional examinations (ultrasound of the liver, spleen, antibody test, MRI). A blood test for the number of thrombocytes by Fonio will need to be taken regularly.

How to normalize platelet counts

When the platelets are lowered, the doctor prescribes medication. But the patient can make the treatment process more effective:

  • Reduce the intake of salt, alcohol, exclude from the diet of sea kale, red grape varieties;
  • Include in the daily diet of fish, liver, buckwheat, nuts, apples, celery, sweet pepper.
  • Do not take medicines that cause thrombocytopenia (antibiotics, antidepressants).
  • Take synthetic vitamin complexes, including vitamins A, B, C.

At high rates, the level of platelets can be reduced by normalizing the way of life, reducing stress, trauma. Of drugs to reduce platelets will help acetylsalicylic acid. The dose of the drug is prescribed only by a doctor.

You need to make adjustments to your diet:

  • Exclude dog rose, pomegranate, bananas, mango;
  • To consume products containing acetylsalicylic, malic or citric acid and blood thinning (cranberries, beets, sea buckthorn, tomatoes, green tea);
  • Monitor the amount of fluid used, as dehydration leads to an increase in the viscosity of the blood.

These measures help to normalize the level of platelets, the violations of which are secondary (reactive). Primary thrombocytopenia and thrombocytosis are subject to long-term diagnosis and therapy.

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