Alkaline Phosphatase Test (ALP) | Elevated Alkaline Phosphatase

Alkaline phosphatase is a normal enzyme found in the human body. Alkaline phosphatase measures are useful to evaluate liver function and rule out liver disease. There is alkaline phosphatase enzyme throughout the body. It is found in the liver cells but also the kidneys, the digestive system, and the bones.

In this article, we’re covering everything you need to know about this test and how it works. Why would a doctor ask for an alkaline phosphatase test? Why is it useful?

What is Alkaline phosphatase (ALP)?

What is Alkaline phosphatase (ALP)?
What is Alkaline phosphatase (ALP)?

Alkaline phosphatase is an enzyme found in different parts of the body. However, it is used as a liver function test because it is ubiquitous in the liver and not usually found in the blood. When alkaline phosphatase is increased in the blood, it usually comes from liver cells.

In liver hepatocytes, alkaline phosphatase is concentrated in the area where cells join to create a bile duct. In this area, bile drains into a receptacle and flows to greater ducts into the gallbladder. This enzyme is found on the outer layer of the membrane and interact with substances outside of the cell.

As an enzyme, what alkaline phosphatase does is speeding up chemical reactions. In this case, it breaks down organic phosphate esters through a process known as hydrolysis. But the function of the enzyme does not influence in alkaline phosphatase tests. They are increased in the blood when the liver’s bile ducts are obstructed. Thus, they are used as blood markers of cholestasis.

Written by Martin Davis