Alkaline Phosphatase Test (ALP Test)

Overnight Fasting is preferred.

Alkaline Phosphatase (ALP) Test Overview

An ALP test, which stands for Alkaline Phosphatase test is used to measure the amount of ALP in your blood. Alkaline phosphatase is an enzyme found in the tissues of your body. This enzyme is present in higher amounts in your liver, bones, and bile ducts. The ALP test is used to check for liver function, bone disorders, or bile duct obstructions. This test is not conclusive and can’t definitively diagnose any condition, however, higher ALP levels in your body do warrant medical attention to understand the underlying cause.

When is an ALP Test Prescribed?

An ALP test is prescribed by doctors as a part of monitoring certain symptoms and conditions. This is not a screening test and is used in most cases as a way to understand the root cause of symptoms and conditions a patient is facing. Here are some of the most common scenarios where an ALP test is prescribed to patients.

• Liver function testing. In case of liver function testing, doctors may use this test as a screening diagnostic test for patients with risk factors for liver disease. It can even be used to diagnose liver disease if patients are showing symptoms.
• Paget's disease or bone tumors are also diagnosed using the ALP blood test.
• For symptoms of jaundice and abdominal pain, doctors can prescribe an ALP blood test to check for bile duct obstructions.

Components of an ALP Test

The expected normal range for ALP in your body is 44 to 147 international units per liter (IU/L) or 0.73 to 2.45 microkatal per liter (µkat/L). The range can vary slightly from laboratory to laboratory. In case if your results are abnormal, it can indicate certain health conditions based on if your results are higher or lower than the normal range. Here are some of the conditions associated with abnormal ALP test results. 

• Higher than normal ALP blood test results can indicate liver disease, liver cancer, cirrhosis, gallstones, bile duct obstructions, and certain bone disorders.
• Lower than normal ALP blood test results can indicate magnesium and zinc deficiency and a rare genetic disorder known as hypophosphatasia (HPP).

Procedure And Prerequisites

As a normal blood test, the process used is very simple. Doctors draw blood from the veins in your arms using a needle and send the sample for testing. As a prerequisite, you may be asked to practice overnight fasting before the day of the test.