Visits to the laboratory

General indications

• We have organised and scheduled your attendance to avoid crowding in the waiting rooms, so you must arrive punctually for your appointment. If you arrive well in advance, please wait outside the hospital grounds.
• A maximum of two people may accompany the patient.
• Before going to the sample reception desk, you must validate your health card on the device you will find on arrival.

Blood tests

What is a blood collection and how is it performed?

A blood collection or blood test is a simple procedure that involves collecting a small amount of blood by means of a prick with a fine needle. Specialised staff perform this procedure (in this case, on pediatric patients). Once the blood has been collected, it is sent to the laboratory for analysis. The first option is always to puncture the arm. However, in infants, it can sometimes be done in other areas.

What is a blood test for?

The blood test is used to determine the patient’s health condition. The blood contains information that the medical team can use to establish the diagnosis and treatment, or to see how the therapy the patient is undergoing is working.

Is it a painful test?

Children may think drawing blood is difficult and painful. But nowadays, blood tests cause little discomfort. At the Sant Joan de Déu Laboratory, we want them to get ready for this test with the help of their parents, so they do not arrive worried and frightened by the needle prick. We explain everything in this video.

What is the test procedure? 

1. An elastic band is placed on the arm above the elbow. This tape tightens a little and makes it easier to see and choose a vein. 
2. Once the vein has been chosen, the area is cleaned with cotton wool and surgical spirit. The child will feel a coolness in the arm due to the effect of this cleaning. 
3. The vein is punctured, and only the necessary blood is removed. The child will feel a prick or a mosquito bite. Sometimes more than one needle prick is needed. 
4. The elastic band is removed from the arm and the needle. 
5. The area where the prick was made is covered with a plaster or cotton wool. It will be necessary to put pressure on the area for a few minutes. 
6. The blood is put into a tube and taken to the laboratory for analysis. 

How can I prepare my child for the blood test?   

The imminence of the medical test can cause anxiety. When children are nervous, their blood vessels constrict, making it more difficult to draw blood. For this reason, they must come as calm as possible. To prepare children at home before arriving at the hospital, the following general considerations can be taken into account: 

• They need to know where they are going. It is advisable to tell children the truth and explain that they are going to the hospital for a blood test. If they put up any resistance, it is important to ask why: we might find out if there is something they are afraid of. 
• What to explain? It is recommended that you tell them clearly and simply what a blood collection consists of. This explanation should be adapted to each child’s age, characteristics, and needs to learn about the procedure. It should be borne in mind that the details reassure not all children of the test they will undergo, so if they do not want to know the details, this should be respected.
• In most cases, parents can be with the patient during the extraction. It is important to explain that they can be accompanied whenever possible and if they wish to be. 
• It is recommended they come in calmly. To help them arrive relaxed, they can be distracted with whatever they wish before the test.   

What needs to be considered, depending on the type of patient?

• Infants: at this stage, children are sensitive to sensory stimuli (sound, touch, etc.). Parents or caregivers should be nearby during the extraction, as it can be reassuring for them. If there is an object or toy that relaxes the child, take it with you to distract them during the prick. 
• Patients up to 12 years of age. If it is the first time and they want to learn about the procedure, explain it to them in a simple, clear way adapted to their age, characteristics and need to know. If it is not the first time, listen to what they need and what could make the procedure easier. 
• Adolescents. It may be the first time they have had blood drawn, or they may already be familiar with the procedure. It is important to listen to them and explain what they need to be reassured. 
• Patients with cognitive impairment. They are sensitive to sensory and unfamiliar stimuli. It helps if they are accompanied by people they already know, and distracted by something that relaxes them, such as music or caresses. Caregivers know what can calm them during the procedure: communicate this to staff and bring objects or toys that can make the test easier. 
• If you think the extraction may be a difficult time for your child or adolescent, contact the Child Life team, which helps patients with great difficulty coping with medical procedures. 
• In some specific cases, analgesics (such as sucrose in infants or a cryo-anesthetic cold spray) may be used to reduce anxiety and pain. 

For how many hours is fasting necessary?

In most cases, it is necessary to do the test without eating for a few hours to interpret the results correctly. Regarding fasting, the number of hours that should elapse without ingesting food is determined by age ranges. The general guidelines are as follows: 

• 8 hours, normal fasting. Generally, children over 3 years of age have their blood samples taken under 8-hour fasting conditions. This means 8 hours must have passed since the last meal to do the test. If they are thirsty, children can drink water up to the time of the test. 
• Between 1 and 3 years. fasting for 3 hours. They can drink some liquid (milk or natural fruit juice) when at least 3 hours elapse between the intake and the test. 
• Fasting in infants: 3 hours. In the case of infants, the ideal time to extract is just before feeding, when babies have gone around 3 hours without taking any food. 
• Fasting is not necessary: some tests do not require hours without food, such as genetic tests, certain allergy studies or preoperative controls, among others.
• Drug analysis. If it is an analysis of the levels of a certain drug, it must be taken into account that the patient should not take it before the extraction, as this analysis is performed to ascertain the pre-dose values.   

What needs to be taken into account during the test?

• Children must remain still during the test. It is helpful to know what things relax or distract the patient from making the extraction easier. 
• Immobilisation. This consists of keeping the child restrained to avoid sudden movements during the test. While it is not necessary to immobilise all patients, it is important to understand that this is done to guarantee the success of the test and the safety of the child. 
• Does it hurt? Children often ask this question. Be honest; tell them they will feel the needle prick, but that it does not hurt much and lasts for only a few seconds. 
• It is important to tell the children how brave they are. If we do so, this praise from parents and professionals will be well received. The hospital's extraction booths have bravery certificates and colouring books. Ask the staff if you think it is a good idea.