Does Hemastix differentiate between human and animal blood?

• A. Yes
• B. No
• C. It differentiates human only
• D. It differentiates animal blood

Answer: (B)

Hemastix is a presumptive test for the presence of blood. It works by using the peroxidase activity of the heme group in hemoglobin to produce a color change. Because this reaction detects hemoglobin itself rather than identifying the source, it cannot distinguish between human and animal blood. Human and animal blood both contain hemoglobin with similar chemical properties, so a positive result tells you blood is present but not its species. To tell human from animal blood, you’d use species-specific tests such as human-targeted immunoassays or DNA analysis. Be aware that Hemastix can yield false positives from substances with peroxidase activity, so positive results should be confirmed with additional tests.