Pediatrics

As pediatrics is the branch of medicine that deals with pathologies from infancy to post-adolescence, the challenge of pediatric biomarkers is to be able to assist in diagnosis and screening by performing biomarker assays with a very small sample quantity. Some parameters require the establishment of specific standard values for different age groups, especially at puberty.

Pediatric biomarkers: diagnose and screen with a very small sample quantity

As pediatrics is the branch of medicine that deals with pathologies from infancy to post-adolescence, the challenge of pediatric biomarkers is to be able to assist in diagnosis and screening by performing biomarker assays with a very small sample quantity.  Some parameters require the establishment of specific standard values for different age groups, especially at puberty.

Most routine tests in infants and children do not require invasive procedures.  However, in the first week of life, the infant will have a blood test commonly known as the Güthrie test.  This test is used to detect certain rare diseases.

C-reactive protein: a key marker in pediatrics

C-reactive protein (CRP), which does not cross the placenta, is a marker of choice for differentiating inflammation of maternal origin from inflammation specific to the child. In neonatology, a value of less than 5mg/l is generally sufficient to rule out a bacterial infection. In pediatrics, a threshold value of more than 20mg/l, before the age of 6, is in favor of a bacterial infection.

Another indicator to monitor in pediatrics: IgA

In children, plasma IgA levels are very low during the first few months of life and only reach values close to those of adults between the ages of 6 and 11.  Undetectable IgA levels at the age of 12 months are, however, suggestive of IgA deficiency.  Congenital IgA deficiency is the most common immunodeficiency in children.  Selective IgA deficiency is defined by the European Society for Immunodeficiencies (ESID) as a serum IgA level of less than 0.07g/l in a patient over 4 years of age after exclusion of other causes of hypogammaglobulinemia.

Allergic diseases in children

Allergic diseases in children are increasingly present nowadays, currently affecting 1 in 3 children.  Among these diseases, respiratory and food allergies are the most common.  In the case of IgE-mediated allergy (immediate type), in-vivo (skin) and in-vitro (IgE assay) tests are performed.  The diagnosis of non-IgE-mediated allergy (usually of later expression) is mainly based on clinical findings.

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