The present invention relates to a diagnostically useful carrier comprising a means for specifically capturing an antibody to Ara h 7 isotype 7.0201 in a sample from a subject a method comprising the step detecting in a sample from a subject the presence or absence of an antibody to Ara h 7 isotype 7.0201 and a pharmaceutical composition comprising Ara h 7 isotype 7.0201 or a variant thereof.