Blood test in children, preparation and parameters

blood, stool and urine tests help us to refine more to be able to determine a disease in the child. In addition, in children, routine tests are not necessary if there is no very specific cause that justifies them. In this article we will focus on blood tests in children.

What is a blood test and what is it for?

It is a laboratory test where the different components of the blood are analyzed. Its removal is not pleasant but it is not very painful either. What happens is that needles are always scary. blood is made up of 45% cells (white, red blood cells, and platelets) and 55% plasma (the liquid part of the blood, made up of 90% water, proteins (albumin, immunoglobulins, and clotting factors). ), enzymes, hormones, glucose, fats (cholesterol and triglycerides), mineral salts, gases in solution and vitamins. When we do one we do not ask for everything we can find, but only those substances that will allow us to carry out the correct orientation of the child. With the analysis of a small sample of venous blood we can know, roughly, if our body works well. In addition, in serious infections, we can also culture the blood (this is called a blood culture) to observe the growth of some bacteria and to be able to give the best antibiotic treatment.

Are blood tests in children fasting?

In most cases we must obtain the sample with a minimum of eight to 12 hours of fasting, that is, without ingesting any food (water is allowed). Glucose (blood sugar), or some hormones, such as thyroid, are best evaluated if the child has not eaten at all. Only in newborns, infants or some children with metabolic diseases is it not necessary to perform the analysis in the fasting state.

Strategies to Prepare Your Child for a blood Test

The needles used for tests in children are thinner than in adults. The staff is highly qualified to perform the technique quickly and painlessly. Still, fear is the great enemy. In children who can understand it, it is important to explain the procedure and that the parents are present during the extraction, so the child will feel more calm and accompanied. In some cases, pain relievers (such as sucrose in newborns) or topical anesthetics cream may be used to decrease pain. The puncture of the vein is carried out with a needle that is finer than the one used in adults, after disinfecting the skin. In addition, a rubber strip-shaped compressor is placed to facilitate the rapid filling of the veins and facilitate the extraction of blood.

Are preventive tests necessary in the follow-up of the healthy child?

No. There is no evidence or recommendation to perform routine tests in children who do not need it or within the well-child health program. Therefore, children without notable health problems do not have to undergo "preventive" tests.

When are blood tests necessary in children?

There are conditions that do justify the performance of periodic follow-up tests in children:

• Familial hypercholesterolemia (genetically caused high cholesterol levels).
• Metabolic diseases.
• diabetes.
• Chronic and hormonal diseases.
• Chronic taking of drugs, such as anticonvulsants (medicines for epilepsy): to control drug levels in the blood or evaluate their side effects.
• Immunodeficiencies.
• Child with cancer.

In children without chronic problems, we may need laboratory tests to study potentially serious illnesses that appear acutely or unexpectedly, such as a serious infection, anemia, or poisoning. Or for the study of diseases not so serious, but with an impact on the habits of the child, such as allergies.

If you are concerned about the health of your children or need to regularly monitor certain values, you may be interested in l for any age.

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What parameters are most frequently evaluated in a blood test in children?

The analytics are always requested under medical criteria and it is the doctor who selects the parameters to be evaluated:

• blood count: The three main cells of the blood (red blood cells, leukocytes and platelets) are analyzed. It is very important to rule out anemia or the presence of an infection.
• Coagulation: in cases of surgery it is vitally important to know how the patient coagulates, that is, their ability to plug possible wounds. It is very important for safe surgery.
• Liver (liver) function: enzymes such as transaminases and bilirubin are determined. They are markers that show us if the liver is inflamed or if it is not working well.
• Renal (kidney) function: ions in the blood, urea and creatinine give us an idea of ​​how the kidneys work.
• Lipidic profile: indicates the level of triglycerides and cholesterol.
• Proteins that indicate infection or inflammation: such as ESR or CRP.
• blood glucose: important for assessing glucose (sugar) metabolism.

• There is no evidence or recommendation to perform routine tests in children who do not need it or within the well-child health program.
• There are conditions that do justify the performance of periodic follow-up tests in children (familial hypercholesterolemia, diabetes, taking drugs, cancer ...)
• The needles used for tests in children are thinner than in adults. The staff is highly qualified to perform the technique quickly and painlessly.

Pediatric specialist

Advance Medical collaborating physician