What indicates a positive acid phosphate test?

• A. The solution turns orange.
• B. A purple color appears when the test solution is added.
• C. No color change is observed.
• D. The test forms a precipitate.

Answer: (B)

The test is measuring acid phosphatase enzyme activity, which is abundant in semen. When a substrate for acid phosphatase is present, the enzyme converts it into a colored product. A purple color after adding the test reagents indicates that acid phosphatase is present, signaling a positive result consistent with semen. If there’s no color change, or the solution only turns orange or forms a precipitate, those outcomes do not indicate a positive ACP result under the standard procedure.