Platform | Preferred Volume, mL | Minimum Volume, mL |
EIA IgE | 0.50 | 0.30 |
CAP IgE | 0.50 | 0.34 |
CAP IgA | 0.50 | 0.15 |
CAP IgG | 0.50 | 0.15 |
CAP Ig4 | 0.50 | 0.15 |
Cross-reactivity occurs when antibodies created against one allergen respond to a different allergen that is biologically related. For example, research has shown that there is cross-reactivity among crustaceans, so people allergic to one type of shellfish are cautioned to avoid eating other kinds as well.
It is important to note, however, that cross-reactivity is not absolute and can vary. A patient's immune system may not respond, or respond equally to foods belonging to the same family. It is thus up to the physician to decide if testing for cross-reactive foods is appropriate, and if so which assay is to be performed when no test is available for the desired allergen.