Phadia’s F1 test is used to detect blood levels of IgE (antibodies) responsible for the often severe allergic reactions to raw or cooked egg whites. The interpretation chart accompanying the results expresses the probability of an allergic reaction to egg whites, but not necessarily the severity of the reaction. Case history (age, symptoms, relation to meals, etc.) and clinical examination by the physician are essential for a reliable interpretation of the results.
An anti-egg white IgE result below 0.35 kilounits per litre (< 0.35 kU/L) indicates that egg whites are probably not responsible for the symptoms observed, but it DOES NOT COMPLETELY RULE OUT THIS POSSIBILITY. A result above 7 kU/L indicates a greater than 95% probability of allergy while a result > 50 kU/L predicts the probable unlikelihood of remission. However, a decline in these results over time points to the possibility of remission. Testing for anti-egg allergen IgE (ovomucoid, ovalbumin, etc.) may help in some cases to clarify whether the person is allergic to both raw and cooked eggs (positive ovomucoid) or only cooked eggs. The double-blind oral food challenge remains the definitive technique for confirming the presence or absence of a food allergy.