Hematic Table: Definition, Objectives, Results, Detectable Diseases and Previous Preparation

Also called a complete blood count, it is one of the most common blood lab studies.

The complete blood count is performed by calculating the elements present in the blood.

These analyzes are usually done with the help of special equipment, and even the calculations are determined by these machines that analyze the different components of the blood in a short time.

The values ​​of the concentration of white blood cells, red blood cells, and platelets in the blood are essential aspects of the complete blood count.

Usually, in a complete blood count, the doctor expects to be able to evaluate the general state of the patient’s health through the values ​​reflected in the said examination.

It also hopes to detect many diseases, including anemia, infections, and leukemia.

With the help of a complete blood count, the levels in which several components are found and several characteristic values ​​present in the blood can be measured.


The blood count lists several essential values, which usually include the following:

  • The white blood cell or white blood cell counts represent the number of white blood cells in a given blood volume. Average white blood cell count values are in the range of 3.5 to 10.5 billion cells / L.
  • The differential count of white blood cells is composed of several different types, such as neutrophils, lymphocytes, monocytes, eosinophils, and basophils, which differ in shape and size. This counting can be done with the help of a computer called the automatic differential.
  • In the red cell count or erythrocyte count, the normal range will vary according to the laboratory, but usually, the average levels are located; in men, they go from 4.32 to 5.72 trillion cells / L and in women, 3.90 to 5.03 billion cells / L. This count determines the number of red blood cells.
  • The hemoglobin levels, a protein present in red blood cells, are considered normal in men, from 13.5 to 17.5 grams / dL, while in women, it is 12.0 to 15.5 grams / dL.
  • The amount of hematocrit is the ratio between the volume of red blood cells and total plasma volume. The normal levels of Hematocrits are different in each sex; in men, it is from 38.8 to 50.0 percent, and in women, it is from 34.9 to 44.5 percent.
  • The average corpuscular volume is the average volume of erythrocytes or red blood cells. The red blood cell count calculates this value. The normal range is between 80 and 100 fl.
  • The mean corpuscular hemoglobin, which is the measure of the mass of hemoglobin contained in a given volume of red blood cells, presents its normal range between 27 to 32 picograms.
  • The amplitude of the distribution of red blood cells is a measure of variation in the size and shape of red blood cells and appears, along with other hematimetric indices. The higher numbers indicate a more significant variation in length, and the usual range goes from 11 to 15.
  • The platelet count shows the number of platelets found in a given blood volume. Platelets are not complete cells; they are responsible for the blood coagulation processes. Average platelet count values ​​vary from 150 to 450 billion / L.
  • The average platelet volume is the number of platelets in a given blood volume.


A blood count is a blood test that is performed for a variety of reasons, including:

  • For the preventive control of the individual and frequently monitor the state of general health. The doctor can request a blood picture to perform a routine medical examination, also as part of a preventive health check.
  • For the differential diagnosis of a disease. The doctor may suggest a complete blood count if the patient is experiencing weakness, fatigue, fever, swelling, bruising, or the presence of some bleeding.
  • A blood picture will show values ​​that can help diagnose the pathology that gives rise to the signs and symptoms that the patient presents. If the doctor suspects an infection, however slight, with the help of the data shown in the blood picture, you can perform an analysis to confirm that diagnosis.
  • For the control or monitoring of disease. The doctor can perform a complete blood count to monitor the condition and treatment progress.


In general, some medications can affect the blood cell count, so it must be taken into account that the treatments administered can cause changes in the blood cells at the time of analysis.

A complete blood count does not represent the analysis of a definitive diagnosis; some results may exceed the average values ​​without it being necessary to follow up.

The doctor must examine the results of the complete blood picture and other types of blood tests and complementary studies.

Thus in cases of slight variations in a healthy person, it may not be a cause for alarm. Still, in the case of a patient with oncological treatment, results slightly lower or higher than average values ​​may indicate the requirement of a modification of the scheme of treatment.

Variations such as the increase or an abnormal reduction in the values are evidenced through the complete blood count.

It could give indications of an undiagnosed disease, which should be evaluated in greater depth through other diagnostic mechanisms.

In results with a significant variation concerning average values, the doctor should refer the patient to a specialist in blood disorders, a hematologist.

So when results are observed as high values ​​in a white blood cell count, this can mean the presence of an infection in some part of the body.

It may also indicate the presence of an underlying neoplasm malignancy.

A count with low levels of leukocytes or leukopenia may indicate a problem in the bone marrow or may be related to the administration of some medication, such as chemotherapy.

Counts of red blood cells, hemoglobin, and hematocrit are intimately related because they measure different aspects of red blood cells.

A low level of red blood cell count or low hemoglobin levels may suggest anemia, may also indicate diseases of the bone marrow, or low levels of oxygen in the blood.

A higher than average red blood cell count, hemoglobin, or hematocrit may suggest heart disease.

When there is a low level of platelet count, these results may be due to prolonged bleeding or a condition in the production of platelets in the bone marrow.

And if, on the contrary, a high platelet count is observed in the test, this may indicate a bone marrow problem or the presence of some severe inflammation.

Detectable diseases with a complete blood picture

The doctor can recommend or order a complete blood picture when patients show signs of infection, weakness, or tiredness, even with inflammation, bruises, or hemorrhages.

The presence of abnormal results can support the diagnosis of some diseases, such as:

  • The infections
  • Inflammations
  • Cancer.
  • To leukemia.
  • Diseases that attack the body’s immune system.
  • Failures in the spinal cord.
  • Abnormal developments of the spinal cord.
  • The anemia
  • Dehydration or loss of fluids in the body.
  • Deficiencies of vitamins and minerals.
  • Thalassemia or abnormal production of red blood cells.
  • The effects of chemotherapy or radiotherapy.
  • The results of certain antibiotics.
  • The impact of prolonged and even short-term use of certain types of medications.

Previous preparation

In a blood picture, only a count of the blood components is made; that is why if the patient decides whether or not to keep the fast, this decision will not affect the results of the examination.

If the sample of blood taken is only going to be used for this test, it is not necessary to keep the fast; that is, you can eat and drink everything you want before sampling.

However, with this type of exam, it can be requested together with other additional exams if they require a minimum fast of eight hours for the subsequent taking of the sample.