Alkaline phosphatase (ALP) is an enzyme found throughout the human body. It facilitates various biological processes, including bone mineralization and liver activity.
Understanding Alkaline Phosphatase
Alkaline phosphatase helps break down phosphate compounds by removing phosphate groups from molecules, a process called dephosphorylation. It is active and abundant in the liver, bones, kidneys, and intestines, and notably present in the placenta during pregnancy.
In bones, ALP plays a role in formation and mineralization. In the liver, it contributes to bile production and fat breakdown. The enzyme also aids in nutrient absorption in the intestines.
Interpreting Your Alkaline Phosphatase Level
Normal ALP levels can vary based on age, gender, and the specific laboratory’s reference ranges. For adults, a common general reference range might be around 20-140 U/L or 44-147 IU/L. Each laboratory establishes its own “normal” ranges.
A value of 138 U/L or IU/L typically falls at the higher end of what is considered a normal range for many adult reference scales. Depending on the laboratory’s upper limit, it might be considered slightly elevated. A single numerical result like 138 is rarely diagnostic on its own. It requires interpretation within the broader context of an individual’s overall health and other medical information.
Factors Influencing Levels
Numerous conditions and physiological states can influence alkaline phosphatase levels. Elevated ALP levels are frequently associated with liver-related issues, such such as bile duct obstruction or hepatitis. Bone conditions also commonly cause increases, including periods of rapid bone growth in children and adolescents, healing fractures, or diseases like Paget’s disease.
Other less common causes for elevated ALP include certain kidney diseases, some cancers, and heart failure. Physiological increases are also observed during pregnancy due to the presence of placental ALP. Certain medications can also lead to an increase in ALP activity.
Conversely, lower-than-typical ALP levels are less common but can occur. These might be linked to conditions such as malnutrition, particularly a zinc deficiency. Certain rare genetic conditions, like hypophosphatasia, which affects bone and tooth development, can also result in unusually low ALP levels.
Next Steps After an Abnormal Result
If an alkaline phosphatase level is outside the typical range, consulting a doctor is the appropriate next step. The doctor will consider the ALP result with the individual’s complete medical history, a physical examination, and any other relevant blood tests. This comprehensive approach helps understand the full clinical picture.
Potential follow-up tests might include additional liver function tests, such as bilirubin or gamma-glutamyl transferase (GGT), to further assess liver health. Bone isoenzyme tests can help determine if the elevated ALP is primarily coming from bone or liver sources. Imaging studies may also be ordered if a specific organ issue is suspected. An ALP level is one piece of information that contributes to a broader understanding of health, rather than providing a definitive diagnosis on its own.