What can the IgE Allergietest tell you — and what not?

The IgE allergy test (specific IgE) measures the concentration of antibodies against specific allergens in the blood. It indicates whether sensitization exists – i.e., whether the immune system reacts to an allergen. This is useful for identifying potential triggers in allergic diseases such as hay fever, asthma, or insect venom allergy. However, a positive IgE level does not necessarily mean that clinical symptoms will occur. Many people have IgE against pollen without ever experiencing symptoms (silent sensitization). Conversely, a negative test cannot reliably rule out an allergy, because not all relevant allergens may be tested or non-IgE-mediated reactions may be present. The test is not suitable for diagnosing food intolerances (lactose, histamine) or non-allergic conditions. The gold standard for diagnosing food allergies remains the oral food challenge under medical supervision. Similar limitations apply to skin prick tests. An IgE test is one piece of the puzzle but never the sole basis for decision-making. Interpretation should always be done by an allergist.