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¿Sabes interpretar los resultados de un hemograma?

¿Sabes interpretar los resultados de un hemograma?

Top Doctors
Top Doctors editorial
Top Doctors
Created by: Top Doctors editorial
Edited by: TOP DOCTORS® at 11/06/2019

The blood count is one of the laboratory tests most used by doctors to study any patient. Only in the Community of Madrid almost three million blood tests are performed per year. The objective of this study is to assess the cellular components of the blood (red blood cells or erythrocytes, white blood cells or leukocytes and platelets) and a series of parameters related to them.

 

Alterations of the normal values ​​of the hemogram occur both in diseases of the blood and diseases of other organs. A very important number of diseases will have an expression in the blood count so it is considered an essential test in the medical assessment of a person.

 

The blood count is one of the laboratory tests that we use most

 

How the blood count test is performed

This test is performed with a laboratory device called "automatic blood count". This is a very standardized study from which all laboratories will give us the same parameters when requesting a blood count. If we make a general analysis for a medical problem or for a check-up, when we pick them up probably on the first page we will have the blood count.

 

When we start reading it we find a series of acronyms or abbreviations that many times we are not able to interpret. If, in addition, we find some values ​​in "bold" or with an arrow up or a date down, some uneasiness can start in our mind. The doctor. Google can then calm us down or lead to total confusion. For everyone's peace of mind, most of the alterations observed in a hemogram are usually not relevant.

 

From a practical point of view, the blood count can be divided into three parts; those related to red blood cells and their oxygen transport function, those related to the number of white blood cells and, finally, those related to platelets.

 

The blood count can be divided into three parts

 

Parameters related to red blood cells

The most important parameter for assessing red blood cells and their function is hemoglobin. Sometimes we are worried about the hematocrit or the number of red blood cells, but these values ​​have more variability. It must be remembered that normal hemoglobin values ​​vary with age and sex; A 20-year-old man is not the same as a small child or an elderly woman of 90 years.

 

If hemoglobin is normal for our sex and age, although there are alterations in the rest of the parameters related to red blood cells, it is rare that there will be a relevant health problem. When hemoglobin is low we have anemia. If the hemoglobin is high we have polyglobulia or polycythemia. The causes of anemia are multiple, with bleeding and iron deficiency being the most frequent. Regarding the causes of increased hemoglobin, the most frequent are smoking and respiratory problems, including sleep apnea.

 

The hematocrit corresponds to the percentage occupied by the red blood cells of a sample of whole blood. It is related to the number of red blood cells and hemoglobin; if it only has a less relevant value than hemoglobin.

 

The number of red blood cells or erythrocytes also has less value than hemoglobin and is usually related to it. Generally the hematocrit and the number of red blood cells help the doctors to see if there is congruence in the results and to guide the diagnosis in case of anemia or polyglobulia.

 

The rest of the parameters are the so-called erythrocyte indices:

 

  • Mean Corpuscular Volume (MCV): This refers to the size of red blood cells that, in case of anemia and being altered, helps doctors to know the cause. The small size of red blood cells (VCM ↓) is often associated with iron deficiency and chronic bleeding. The large size of red blood cells is usually relevant if it is important and is mainly related to vitamin B12 or folic acid deficiency.

 

Erythrocyte indices

 

  • Average corpuscular hemoglobin (HCM): the average hemoglobin amount of a red blood cell. A low HCM indicates the decrease in hemoglobin content for each red blood cell.
  • Concentration of mean corpuscular hemoglobin (CHCM): the amount of hemoglobin relative to the size of each red blood cell. If it is elevated, it usually indicates the presence of small red blood cells loaded with hemoglobin and vice versa.
  • ADE or IDE; is the erythrocyte scattering index or the amplitude of the erythrocyte distribution curve. It is a way to measure the "uniformity" of the red blood cells. A high figure means that there is no uniformity and we will find both very small and very large red blood cells.. It is typical of deficiencies of iron or vitamins.

 

The erythrocyte indices are results given by the hematological counters and usually have no meaning if the hemoglobin and the rest of the main parameters are normal. If there is anemia, they will help us to guide the cause of it.

 

Parameters related to white blood cells

In the blood count the white blood cells are called leukocytes and the result that is offered is: on the one hand, their total number, and on the other hand, the number of each one of the subtypes of the same (in percentage or absolute number).

 

The number of leukocytes is very variable. They are affected by many processes most of them banal. Only extremely low or high amounts of leukocytes, which appear unexpectedly, are associated with relevant health problems.

 

The most relevant type of leukocyte are neutrophils, which defend us from infections. Low figures are seen in many situations and are not usually especially relevant, especially if the patient is asymptomatic and there is no apparent cause. Figures below 1000 may require additional studies. Slightly high figures are seen in many situations, including habitual smokers.

 

Lymphocytes are the second most abundant type of leukocytes. They are responsible for more specific and selective immunity. They also have a great variability and only very large or very diminished figures that appear unexpectedly could be relevant.

 

Monocytes are first-line phagocytic cells of our defense system against infections. Their number also has a great variability and only very striking figures that appear unexpectedly could indicate some significant disease.

 

Eosinophils are a type of leukocytes that are altered with certain frequency in patients with allergy, asthma and infections by parasites. Its elevation can be a marker of them. Low numbers of eosinophils are rarely going to have a meaning on their own.

 

 

Basophils are a type of leukocytes in general not very relevant, being a usual marker of a type of blood diseases called myeloproliferative syndrome.

 

Parameters related to platelets

The number of platelets is a fundamental parameter of the blood count, with the rest being low-value platelet indexes. Small alterations in the number of platelets are very frequent and do not usually indicate relevant problems. The number of platelets clearly decreased below 100,000 per microliter or clearly increased (> 400,000), without apparent cause, usually requires study.

 

Hematological counters automatically give us a series of secondary parameters called platelet indexes that have no value if the platelet count is normal. The average platelet volume, if it is increased in a patient with low platelets, usually indicates larger platelets than normal and supports that the cause is an excess of consumption of the same. The plaquetocrito or the platelet distribution curve have a very limited utility in the orientation of a patient with a low number of platelets.