Routine blood test results – Alkaline phosphatase (AP, ALP)

Alkaline phosphatase is an important enzyme found in various tissues of the body and plays a role in the breakdown of proteins. The determination of enzyme levels is conducted during laboratory tests, most commonly through a blood sample. The purpose of this test is generally to assess the condition of the liver and bones, but it is also frequently encountered as part of routine check-ups.

The level of alkaline phosphatase in the blood provides significant information about the functioning of the body. The normal value of the enzyme ranges from 20 to 140 U/l and is found in various tissues such as the liver, gallbladder, intestines, bones, kidneys, and placenta. There are three main types of the enzyme: intestinal, placental, and non-specific types, but the most common are the liver and bone-specific forms.

Decreased Alkaline Phosphatase Levels

The decrease in alkaline phosphatase levels occurs relatively less frequently than increased values. Low activity can arise from several reasons, including starvation and severe malnutrition. Additionally, individuals struggling with malabsorption disorders who are lean may also experience reduced levels of the enzyme.

Other possible causes include conditions following severe intestinal inflammation, which also reduce enzyme activity. It is important to note that low alkaline phosphatase levels should not be used as a standalone diagnosis; other laboratory results and the patient’s overall health status must always be taken into account.

Low alkaline phosphatase levels can be a warning sign that may require further investigation to uncover the underlying cause. For physicians, interpreting decreased levels necessitates a comprehensive analysis of the clinical picture and additional laboratory tests.

Increased Alkaline Phosphatase Levels

Increased alkaline phosphatase levels are a much more common phenomenon and are associated with various diseases and conditions. Elevated values are often linked to liver diseases such as hepatitis, cirrhosis, or fatty liver disease. Problems with the gallbladder and bile ducts, such as cholangitis or obstruction, can also contribute to increased enzyme levels.

Bone diseases such as osteomalacia, Paget’s disease, and malignant tumors with bone metastases can also elevate alkaline phosphatase levels. Additionally, certain hematological disorders, such as bone marrow fibrosis, may play a role in the development of elevated values.

Not only diseases but also physiological conditions can affect alkaline phosphatase levels. Pregnancy, sarcoidosis, myocardial infarction, as well as hyperthyroidism and hyperparathyroidism can all contribute to the increase in enzyme levels. It is important to emphasize that an increase in alkaline phosphatase levels does not constitute a standalone diagnosis and should be evaluated in conjunction with other laboratory results.

In cases of liver or bile duct problems, it is essential to examine other indicators, such as bilirubin or transaminase levels, alongside the elevated enzyme level to establish an accurate clinical picture.