TRAP 5b (Tartrate-Resistant Acid Phosphatase 5b)

TRAP 5b is an enzyme that is specifically released by osteoclasts (bone-resorbing cells). The laboratory value measures the concentration of TRAP 5b in the blood and is used to assess bone resorption.

A TRAP-5b test is recommended for: • Patients with suspected osteoporosis or increased bone resorption • Diagnosis of bone diseases such as Paget's disease or bone metastases • Monitoring of patients under antiresorptive therapy (e.g. bisphosphonates) • People with symptoms such as frequent fractures or bone pain

The test serves the diagnosis and monitoring of diseases associated with increased bone loss. It helps to assess the activity of osteoclasts.

A high TRAP-5b value indicates: • Increased bone resorption in osteoporosis • Bone damage from tumors or metastases • Hyperparathyroidism with increased bone metabolism A low value indicates reduced bone resorption, which can occur with successful therapy or low metabolism. Symptoms with elevated values can include: • Bone pain • Frequent fractures

The testing can be carried out at any time of the day, but ideally at constant time points during follow-up checks.

• TRAP 5b is a specific marker for osteoclast activity and therefore particularly useful for assessing bone resorption. • In children and adolescents during growth, elevated values can be physiological. • Diseases such as renal insufficiency can influence the values, which is why they should be interpreted in the context of other markers.