One method of testing for gluten and casein intolerance is determined by the urine peptide test. This test looks for abnormal peptides in the urine.
Some parents implement the diet before lab testing and see proof that the diet works.
Other parents may feel the need for testing to substantiate using the GFCF Diet as an intervention. We feel that because of the successful improvements seen in so many ASD children after strict adherence to the diet, a test is not always necessary. However, keep in mind that lab testing may help some parents make the decision and stick with the GFCF Diet. The IGg food allergy test can also determine food intolerance. It does not check for peptides in the urine.