Cytotoxic food intolerance tests were developed from research that began in the 1950s, was launched in the mid-1980s, and has been marketed since then. Cytotoxic testing uses a technician to examine cells under a microscope to judge whether there was a reaction; some companies improved the test process by applying electronic instrumentation to measure and interpret the changes. Nevertheless, cytotoxic tests were intensely criticized because, in cytotoxic test results, an individual’s day-to-day and month-to-month reactivity showed significant changes, and reproducibility could never be demonstrated.
In the classic direct ELISA technique, an antigen is isolated and then mixed with a blood sample complete with antibodies. A conjugated secondary antibody is added, as this binds to the antigens along with the original antibodies, resulting in more visible detection of a problem food.
Microarray technology is slightly different. A microarray slide is produced by isolating protein extracts onto a plastic chip. As with the ELISA technique, the blood sample and primary antibody are added to the chambers attached to the slide. The antibodies bind to the antigens, and a conjugate is added. However, unlike in the ELISA technique, this conjugate is not visible to the eye. Instead, advanced laser scanners are used to give more precise results.
The ELISA technique uses polystyrene plates to perform the analysis. For an ELISA analysis of 192 foods, two large plates are needed. In contrast, protein microarray, uses a tiny glass slide, meaning much less blood is needed. While the ELISA technique requires at least a vial of blood, the microarray method only requires a few drops.
Protein microarrays are more similar to ELISA than Western blot because the samples’ proteins are generally not fractionated before the assay. Instead, the proteins are deposited in small (100-300 urn) spots on a specially coated microscope slide in constructing microarrays. The slide is often coated with a polymer like nitrocellulose or gel that increases the binding capacity of the protein. As a result, microarrays offer the advantages of higher throughput, multiplex analysis, low reagent consumption, high sensitivity, and lower sample requirement compared to either the Western or ELISA assays.
Muscle testing, aka applied kinesiology, Hair Testing, and EAV (electronic testing), are not part of conventional allergy tests. No significant scientific evidence exists that allergies can be diagnosed using these methods.