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Immunoglobulin G in the blood
Medical expert of the article
Last reviewed: 05.07.2025
Immunoglobulin G is the main component of the γ-globulin fraction of blood serum. They make up the bulk of all human Ig (80%) and are the most important effectors of humoral immunity. Various antibodies against bacteria, their toxins, viruses and other antigens belong to immunoglobulin G. They are contained not only in the vascular bed, but also easily penetrate into the extravascular space, where they perform a protective function due to toxin-neutralizing, virus-neutralizing, opsonizing and bactericidal activity. Antibodies of this class are the main protective factor in a child in the first weeks of life (they penetrate the placental barrier into the fetal blood). Half-life is 21-24 days. They activate complement by the classical pathway.
Reference values (norm) of immunoglobulin G concentration in blood serum
Age |
Concentration, g/l |
Children: |
|
1-3 months |
2.7-7.8 |
4-6 months |
1.9-8.6 |
7-12 months |
3.5-11.8 |
2-3 years |
5.2-13.6 |
4-5 years |
5.4-14.2 |
6-7 years |
5.7-14.1 |
10-11 years |
7.3-13.5 |
12-13 years old |
7.7-15.1 |
Adults |
8-17 |
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