One of the modern methods for determining allergies in babies is a blood test of children. This method has its advantages over traditional skin allergy tests.
Why donate blood?
In the blood of a child with allergies, antibodies are present, which are formed during allergic reactions. They are represented by class E immunoglobulins. A blood test is aimed at identifying these antibodies, during which you can simultaneously find out the effect of tens of allergens on the child's body.
With this method of allergological examination, the child will not have a clinical reaction to allergens, and an increased level of Ig E will indicate the presence of allergies.
Indications
A blood test is carried out when:
- Hay fever;
- Eczema;
- Drug allergy;
- Bronchial asthma;
- Atopic dermatitis;
- Food allergies;
- Helminthiasis;
- Inflammatory diseases of the respiratory system.
It is also advised to donate blood to assess the risks of allergic diseases in children whose family has patients with allergic pathology.
Pros compared to skin test
- The child does not come into direct contact with allergens, so a blood test is safe and can be performed at any stage of allergic diseases.
- The accuracy of the blood test is very high. Tests help identify specific allergens that are harmful to the baby.
- One analysis is enough to detect a reaction to dozens of allergens.
- Such an analysis will help out if the child's skin is damaged.
- It can be done in childhood.
- It will not harm children who have had anaphylactic reactions in the past.
Training
When blood is used to detect allergies, it is recommended to take the test in the morning. It is best if the blood sample is taken on an empty stomach. If the child has eaten breakfast, it is advised to take a blood sample three hours later.
Foods that can cause allergies and contact with pets should be avoided for three to five days before blood sampling. During this period, significant physical activity should also be avoided.
How is the analysis done?
An allergy test requires the child's venous blood. It is often obtained from a vein located in the elbow fold. The nurse tightens the tourniquet above this area to make the vein more visible and full. After puncturing the vein, the required amount of blood is drawn into the test tube. The result is usually given within seven days after blood collection.
Norm values
The normal Ig E level in childhood is the following amount of antibodies:
- From the fifth day of life to 1 year - up to 15 U / ml;
- From 1 year to 6 years of age - up to 60 U / ml;
- From 6 to 10 years old - up to 90 U / ml;
- At 10-16 years old - up to 200 U / ml;
- Over the age of 16 - up to 100 U / ml.
You will see the advantages in the blood test results:
- If there are no pluses, then the level of detected antibodies is less than 50 U / ml;
- "+" Indicates the level of antibodies from 50 to 100 U / ml, that is, poor sensitivity;
- "++" indicates moderate sensitivity and antibody levels from 100 to 200 U / ml;
- "+++" is set at high sensitivity, when the antibody level exceeds 200 U / ml.
