"ALK PHO" on a blood test stands for "alkaline phosphatase test," which measures the level of enzyme ALP in the blood. This test can be used to diagnose liver and bone conditions, such as liver disease or damage, bone tumors and rickets.
A patient receives an alkaline phosphatase test as part of his normal blood test, as described by WebMD. If a follow-up test is required, the patient may be asked to fast for up to 10 hours before the test. ALP levels in the blood can be affected by certain foods and medications. A normal value for an ALP test, for an adult, is 25 to 100 units per liter.