Bluestar detects latent blood stains using which mechanism?

• A. Fluorescence
• B. Chemiluminescence
• C. Colorimetric change
• D. Absorption

Answer: (B)

Bluestar relies on chemiluminescence to reveal latent blood. The reagent contains luminol and an oxidizer; when luminol meets the iron-containing heme in blood, the iron acts as a catalyst and luminol is oxidized. This chemical reaction leaves luminol in an excited state that emits light as it returns to ground state, producing a blue glow that can be seen in a dark room and highlights faint stains. Because the light comes from the chemical reaction itself, no external light source is needed, which distinguishes chemiluminescence from fluorescence. Enhancers in the formulation help boost the brightness and duration of the glow. Be aware that certain substances can also produce a similar glow, so this test is presumptive and may require follow-up confirmation.