Phadia’s F337 test is used to detect blood levels of the IgE (antibodies) responsible for allergic reactions to sole. Sole allergies are caused by parvalbumin, a protein found in many other fish. People who are allergic to sole will usually be allergic to other fish (cod, halibut, trout, etc.) but, unless there is a true double allergy, they will not necessarily be allergic to crustaceans and other seafood. The interpretation chart accompanying the result expresses the probability of an allergic reaction to sole (and possibly other fish), but not necessarily the severity of the reaction. Case history (symptoms, relation to meals, etc.) and clinical examination by the physician are essential for a reliable interpretation of the results.
A negative anti-sole IgE result (< 0.35 kU/L) indicates that sole is 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 medical supervision remains the definitive technique for confirming the presence or absence of a sole allergy. Unlike milk and egg white allergies, the hypersensitivity to sole and other fish often develops in adulthood and tends to persist for life.