Parietal Cell antibody also is known as gastric parietal cell antibody is auto antibodies, proteins that are produced by the immune system, that target the cells in the stomach wall. Parietal cell antibody test helps to detect these antibodies in the blood, which in turn is the cause of pernicious anaemia. Pernicious anaemia happens when the body's immune system prey its own tissues and develops antibodies against the parietal cells and/or intrinsic factor. Parietal cells help in the digestion of the food by making acid and make intrinsic Factor, which is required for the absorption of vitamin B12 from food. Pernicious Anaemia is the most common cause of the deficiency of Vitamin B12.