DefinitionThe antiparietal cells antibodies test measures the presence of antibodies against the parietal cells of the stomach. The parietal cells make and release intrinsic factor and stomach acid. Intrinsic factor is needed to absorb vitamin B12.Alternative NamesAPCA; Anti-gastric parietal cell antibodiesHow the test is performedBlood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed fr