The Organic Acids Test (OAT) evaluates levels of oxalates in urine. Oxalate, is an organic acid that is primarily derived from three sources: the diet, fungus (such as Aspergillus and Penicillium), possibly Candida, and also human metabolism.
Studies show that oxalates in the urine are much higher in individuals with Autism Spectrum Disorders than in non-autistic children.