What is the reported specificity range for ALP staining in detecting osteosarcoma?

• A. 60-80%
• B. 89-94%
• C. 25-50%
• D. 99-100%

Answer: (B)

Specificity is how often ALP staining correctly identifies non-osteosarcoma cases as negative, so a high specificity means few false positives. For ALP staining used to detect osteosarcoma, the reported range of specificity sits in the high 80s to mid-90s. This reflects that a positive ALP stain strongly supports osteogenic activity, but it is not perfect—some non-osteosarcoma bone lesions can stain, and not all osteosarcomas show staining. Among the options, 89-94% best matches the typical literature range, indicating high specificity without implying flawless discrimination. The lower ranges would underestimate the test’s ability to avoid false positives, while a near-perfect 99-100% is not supported by the data.