Results are usually available the next day. Preparation To collect the 5-10 ml blood needed for this test, a healthcare worker ties a tourniquet on the person's upper arm, locates a vein in the inner elbow region, and inserts a needle into that vein. Vacuum action draws the blood through the needle into an attached tube. Collection of the sample takes only a few minutes. A person being tested for alkaline phosphatase shouldn't have anything to eat or drink, except water, for eight to ten hours before the test.
Some people release alkaline phosphatase from the intestine into the bloodstream after eating.
Pressure to the puncture site until the bleeding stops will reduce bruising. Warm packs to the puncture site will relieve discomfort. Normal results Normal results vary by age and by sex. They also vary based on the laboratory and the method used. Abnormal results Bone and liver disease increase alkaline phosphatase more than any other disease, up to five times the normal level.