Mucosal immunity
IgA works where the body comes into contact with the external environment: in the mucus of the respiratory tract, intestines, saliva and breast milk. It does not kill germs, but prevents them from attaching to the mucous membrane - the first line of defense. Selective IgA deficiency is the most common primary immunodeficiency; in many it is asymptomatic, in some it is manifested by frequent respiratory and intestinal infections, allergies and autoimmune diseases. An important practical nuance: in case of IgA deficiency, standard serological tests for celiac disease give a false negative result, so IgA determination must be carried out together with them. Increased levels occur in chronic infections, liver diseases and multiple myeloma.
Why preparation is so important
The laboratory result is a number, but the correct number can only be obtained if the rules are followed. Eating changes the levels of glucose, lipids and a number of enzymes significantly; physical activity the day before increases CK and AST; smoking affects hormones; time of day is critical for cortisol and testosterone.
Therefore, a “bad analysis” often turns out to be a consequence of impaired preparation, and not an illness, and leads to unnecessary examinations and prescriptions.
General rules for donating blood
- on an empty stomach 8–12 hours, you can drink water
- Eliminate alcohol and intense exercise per day
- no smoking in an hour
- donate blood before physiotherapy, x-rays and massage
- Take medications in advance by agreeing with your doctor
- for hormones in women, take into account the day of the cycle
How to read the result
Reference values depend on the method and equipment of the laboratory, so it is correct to compare results only within the same laboratory. A deviation of a few percent from the normal limit in itself rarely matters - the overall picture and dynamics are important. It is up to the physician to interpret the analysis: an isolated indicator without a clinical context is often misleading.