What test is used to check if blood is of human origin –
**Core Concept**
The question is testing the knowledge of a specific test used to determine the species origin of blood, which is crucial in forensic medicine and transfusion medicine. This test relies on the differences in the enzyme composition between human and non-human blood.
**Why the Correct Answer is Right**
The correct test is the **Isotachophoresis** or more commonly known as the **Isotachophoresis test** (also referred to as the **NADH test** or **NADH-diaphorase test**), which detects the presence of NADH diaphorase enzyme. This enzyme is present in human blood and is responsible for the oxidation of NADH to NAD+ in the presence of phenazine methosulfate. The test works by using a substrate that is oxidized by NADH diaphorase, producing a color change that can be detected visually.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely a distractor and does not correspond to any known test for determining human blood origin.
**Option B:** This option is incorrect as the **Hemoglobin test** is used to identify the type of hemoglobin present in blood, not to determine its human origin.
**Option C:** This option is incorrect as the **Blood grouping test** is used to identify the ABO blood group in blood, not to determine its human origin.
**Clinical Pearl / High-Yield Fact**
Remember that the Isotachophoresis test is a reliable method for distinguishing human blood from non-human blood, and it is often used in forensic medicine to identify the source of bloodstains at crime scenes.
**Correct Answer: D. Isotachophoresis test**