**Question:** Coral red colour on wood lamp seen is –

**Core Concept:** Wood lamp test is a diagnostic test to identify the presence of blood in a substance.

**Why the Correct Answer is Right:** The wood lamp test is based on the principle that certain substances, when exposed to the ultraviolet (UV) light, exhibit specific colors due to the interaction between the wavelength of the light and the molecules present in the substance. When blood is present, it contains heme, a protein complex that contains iron and protoporphyrin IX, which exhibits a characteristic coral red color under UV light.

**Why Each Wrong Option is Incorrect:**

A. This option refers to a different substance that might not exhibit a coral red color under UV light, making it irrelevant in this context.

B. This option is incorrect because the wood lamp test is specifically designed to detect the presence of blood in a substance, not other substances like urine.

C. This option is incorrect as wood lamp test is designed to detect the presence of blood, and the color of wood or wood fibers is not related to the test.

D. This option is incorrect because the wood lamp test is designed to detect blood, and substances like wood or wood fibers do not exhibit a coral red color under UV light.

**Clinical Pearl / High-Yield Fact:** Correlation between the coral red color seen on the wood lamp test and the presence of blood is crucial in clinical scenarios, particularly in forensic pathology, to identify bloodstains at crime scenes or in suspected cases of blood ingestion. This test helps in confirming or ruling out blood presence, facilitating further diagnostic or investigative steps.

**Correct Answer:** C. Coral red color on wood lamp test indicates the presence of blood.