Phadia’s F91 test is used to detect blood levels of the IgE (antibodies) responsible for allergic reactions to mangoes. There are different types of reactions to mango, including immediate reactions within minutes of ingestion and delayed reactions that occur from a few hours to several days after exposure and that primarily manifest as dermatitis and periorbital edema (swelling around the eyes). Mangoes are sometimes associated with oral allergy syndrome (symptoms usually limited to around the mouth), a condition associated with many fruit-pollen cross allergies. The interpretation chart accompanying the result expresses the probability of an allergic reaction to mangoes, but not necessarily the severity of the reaction. Case history (symptoms, relation to meals and snacks, contact with the skin of the fruit, etc.) and clinical examination by the physician are essential for a reliable interpretation of the results.
A negative anti-mango IgE result (< 0.35 kU/L) indicates that mangoes are probably not responsible for the reported symptoms but, especially in the case of delayed reactions, it DOES NOT COMPLETELY RULE OUT THIS POSSIBILITY. All negative and positive results must be interpreted in light of the case history. Skin tests can be useful, and the double-blind oral challenge test remains the definitive technique for confirming a food allergy.