Laboratory test for frequent upper respiratory catarrh and infections in children
The most common disease in children is upper respiratory tract infection, which is caused by viruses that attack the airways. These viruses usually enter the airways by droplet infection or by sticking to invisible dust particles, causing symptoms of cold for several days.
In infancy (1-8 years), due to the underdeveloped immune system, children get sick very often as a result of some upper respiratory infection. The number of infections decreases with age due to the development of immunity to certain viruses, and by adolescence, viruses occur as often as in the case of adults.
When is it recommended to have the laboratory package performed?
Laboratory testing for the cause of frequent upper respiratory catarrh is recommended if upper respiratory tract infections occur more commonly than average in children and are often accompanied by complications (e.g. otitis media, pneumonia) or the disease persists for more than 2 weeks and complaints do not improve with antibiotic treatment either.
The laboratory package can be used to find out if the development of frequent upper respiratory tract infections is due to a malfunction of the immune system or some form of hematopoietic disorder.
Which tests does the laboratory package include?
Blood count: is used to determine the relative and absolute number, type, size, shape, and other physical characteristics of the formed elements present in the blood (red blood cells – RBC, white blood cells – WBC, platelets – PLT). The blood count provides information about the status of inflammatory processes in the body, blood loss, dehydration, and can be used to diagnose anaemia, coagulation disorders, tumours of the hematopoietic system (lymphoma, leukaemia), and other hematopoietic diseases (e.g. bone marrow failure).
Inflammatory parameters
Westergren (ESR): by determining the erythrocyte sedimentation rate (ESR), we can get information about the pathological processes present in the body, chronic and acute inflammations, infections, and it can also help diagnose autoimmune diseases. Its elevated value indicates an infection, inflammation present in the body, and may also indicate an autoimmune process.
CRP: Measures the amount of CRP (C-reactive protein) protein produced in liver cells during inflammation. Typically, in the case of bacterial and fungal infections, its levels increase radically within a few hours, so the course of inflammatory diseases and autoimmune diseases can be effectively monitored. A laboratory test can only detect inflammation present in the body, but not its exact location.
Immunological background
Immunoglobulin (Ig) values are usually evaluated together, comparing the differences of the values.
IgG: Immunoglobulin G is the most abundant antibody in the blood. They are produced a few days after infections, providing long-term protection against microorganisms. It helps prevent re-infection with a particular pathogen, so this mechanism is also used by vaccines. When its levels drop significantly, upper respiratory and gastrointestinal infections become much more common.
IgM: in case of infection, the body starts to produce this type of immunoglobulin, which provides short-term protection until IgG production. An increase in its level indicates a recent or existing infection.
IgA: Immunoglobulin A provides primary protection against pathogens on mucosal surfaces (airways and gastrointestinal tract). The amount of IgA in the saliva of patients with recurrent respiratory infections may be lower.
CH50 (total complement activity): The system formed by complement proteins is an innate part of the immune system, involved in destroying foreign substances, recognizing them and activating members of the chain one after the other. The CH50 examines the function of the entire classical complement pathway and all 9 complement components. Lack of one of the complement proteins usually leads to recurrent infections or autoimmune disease. An increased or decreased value indicates whether the immune system is also involved in the inflammatory disease.
AST/ASLO (anti-streptolysin): Anti-streptolysin is an antibody produced against group A Streptococcus by the immune system in response to infection. Bacterial pharyngitis is most commonly caused by members of this group of bacteria. The test can be used to determine its level in the blood, which indicates whether the infection has recently occurred.
Iron metabolism
Iron: It is an important component of haemoglobin, the main oxygen-carrying protein in the blood. In its absence, anaemia develops, reducing the oxygen-carrying capacity of the blood. Iron helps fight infectious diseases and produces proteins. Prolonged inflammatory disease can also lead to iron deficiency.
Transferrin (total iron-binding capacity): It is the main transport protein in the blood from which the body’s iron stores can be inferred. In case of prolonged inflammations and infections, the level of transferrin in the blood increases.
How do I prepare for the test?
Having an empty stomach is not required for the test.
What to do after the test?
The finding alone does not make a diagnosis of any condition or disease; in any case, consult your child’s GP, possibly a paediatric infectologist or paediatric pulmonologist to interpret the findings and discover the cause of the infections.
When is the result expected?
After the 21st working day following the test.
