Orthopaedic Nurses Certification Board (ONCB) Test 2025 – 400 Free Practice Questions to Pass the Metabolic/Inflammatory/Tumors Exam

In Paget's disease of bone, one of the key features is the abnormal restructuring of bone tissue, which is often accompanied by an increased rate of bone turnover. Alkaline phosphatase is a specific enzyme that is produced by osteoblasts, the cells responsible for bone formation. When bone turnover is elevated, as is the case in Paget's disease, alkaline phosphatase levels rise as a reflection of increased osteoblastic activity.

Measuring alkaline phosphatase serves as a useful diagnostic marker. Elevated levels of this enzyme can indicate active bone disease, not just in Paget's disease but also in other conditions characterized by high bone turnover. Understanding this biochemical marker helps in monitoring disease progression and response to treatment in affected patients.

In contrast, while calcium, phosphate, and vitamin D are all important in bone metabolism, they do not specifically correlate with the abnormalities seen in Paget's disease. Calcium levels might fluctuate due to various factors but are not reliably high in this condition. Phosphate levels may also be normal or low depending on other underlying conditions, and vitamin D status does not directly reflect the bone turnover alteration seen in Paget's disease. Thus, alkaline phosphatase remains the most relevant and elevated marker in the context of