Canadian Society for Medical Laboratory Science (CSMLS) Practice Exam

What does an elevation of alkaline phosphatase indicate?

1. Kidney damage

2. Liver disease

3. Bone disorders

4. Hydration status

The correct answer is: Liver disease

An elevation of alkaline phosphatase is a significant indicator in clinical diagnostics, particularly concerning liver health. Alkaline phosphatase (ALP) is an enzyme found in various tissues, but it is especially concentrated in the liver, bile ducts, and bone. When there is an increase in ALP levels, it often suggests that there is a disruption or pathological process occurring in the liver or bile ducts. In cases of liver disease, conditions such as cholestasis (blockage of bile flow), liver tumors, or hepatitis can lead to elevated levels of alkaline phosphatase as the enzyme spills into the bloodstream due to cellular damage or increased production in response to bile duct obstruction. Therefore, measurement of alkaline phosphatase is routinely utilized in the evaluation of liver function and the assessment of liver pathology. Bone disorders, although they can also result in elevated alkaline phosphatase levels, often come with distinct signs and symptoms that can help differentiate their underlying causes. For instance, conditions such as Paget’s disease or osteomalacia may lead to increased ALP, but they are typically associated with changes in bone density or structure and are evaluated through specific tests related to bone health. Hydration status and kidney damage are not directly linked to elevated alkaline phosph