Benzidine test detects –
**Core Concept**
The Benzidine test is a chemical test used to detect the presence of hemoglobin or its derivatives in a sample. It is based on the peroxidase activity of hemoglobin, which catalyzes the oxidation of benzidine by hydrogen peroxide to form a colored compound.
**Why the Correct Answer is Right**
The Benzidine test works by exploiting the peroxidase activity of hemoglobin. When a sample containing hemoglobin is mixed with benzidine and hydrogen peroxide, the hemoglobin catalyzes the oxidation of benzidine to form a blue-colored compound. This reaction is specific to hemoglobin and is not seen with other proteins or substances. The test is commonly used to detect the presence of blood in urine, stool, or other bodily fluids.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the Benzidine test is not specific to detecting the presence of bilirubin in a sample.
**Option B:** This option is incorrect because the Benzidine test is not used to detect the presence of glucose in a sample.
**Option C:** This option is incorrect because the Benzidine test is not used to detect the presence of creatinine in a sample.
**Clinical Pearl / High-Yield Fact**
The Benzidine test is a rapid and sensitive test for detecting the presence of blood in a sample, but it is not specific and can produce false-positive results. It is often used in conjunction with other tests to confirm the presence of blood.
**Correct Answer: A. Hemoglobin.**