Phadia’s F201 test is used to detect blood levels of the IgE (antibodies) responsible for allergic reactions to pecans. The IgE detected in the test may be pecan-specific or involved in multiple allergies with other nuts (walnuts, Brazil nuts, hazelnuts, almonds, etc.) and sometimes peanuts. The interpretation chart accompanying the result expresses the probability of an allergic reaction to pecans, but not necessarily the severity of the reaction. Case history (symptoms, relation to meals, snacks, etc.) and clinical examination by the physician are essential for a reliable interpretation of the results.
A negative anti-pecan IgE result (< 0.35 kU/L) indicates that pecans are probably not responsible for the symptoms reported by the person, but it DOES NOT COMPLETELY RULE OUT THIS POSSIBILITY. Both negative and positive results must be interpreted in light of the case history. The double-blind oral food challenge, under strict medical supervision, remains the definitive technique for confirming the presence or absence of a food allergy. In most cases, allergies to pecans and other nuts are persistent, but it has been shown that some people may get over them.