Which statement best describes the reliability of osteocalcin as a diagnostic biomarker for osteosarcoma in dogs?

• A. It is not specific for OSA in dogs
• B. It is specific for OSA
• C. It is more reliable for chondrosarcoma
• D. It is reliable only in humans

Answer: (A)

Osteocalcin tests what bone formation is doing, so it rises with any process that increases bone turnover. In dogs, many conditions besides osteosarcoma drive osteoblastic activity—fracture repair, osteomyelitis, other bone tumors, normal growth in young dogs, and various metabolic bone diseases can all elevate osteocalcin. That overlap means a high osteocalcin level isn’t specific to osteosarcoma, so it cannot reliably distinguish OSA from other causes of increased bone turnover.

Because of this limited specificity, osteocalcin isn’t a dependable standalone diagnostic biomarker for canine osteosarcoma. It may have research or monitoring roles (for example, in assessing treatment response or prognosis) but not as a definitive diagnostic test.