In forensic investigations, luminol is known to

• A. It produces a faint blue glow when sprayed on bloodstains in the dark.
• B. It detects DNA amplification.
• C. It changes color to red in sun exposure.
• D. It digests blood proteins.

Answer: (A)

Luminol is used to reveal bloodstains by chemiluminescence. When luminol is sprayed on an area that contains blood, the iron in the hemoglobin catalyzes an oxidation reaction in the presence of a small amount of peroxide, producing a faint blue glow in the dark. That glow allows investigators to locate blood that isn’t visible to the eye, which is why the statement about producing a faint blue glow on bloodstains in the dark is the correct description.

The other options don’t fit this test concept. Luminol does not detect DNA amplification, so it won’t indicate genetic testing results. It does not change color with sun exposure, and it does not digest blood proteins.