**Core Concept**
Hydrogen peroxide is used as a reagent in several chemical tests for blood due to its ability to oxidize hemoglobin, resulting in a color change that can be used to detect the presence of blood. This principle is based on the enzymatic reaction catalyzed by peroxidase, which breaks down hydrogen peroxide into water and oxygen.

**Why the Correct Answer is Right**
Hydrogen peroxide is used in the Kastle-Meyer test, the phenolphthalein hemochromogen test, and the leucomalachite green test for detecting blood. In these tests, hydrogen peroxide is added to the sample, and the resulting color change is indicative of the presence of hemoglobin. The peroxidase enzyme present in red blood cells catalyzes the oxidation of hydrogen peroxide, leading to the formation of a colored compound.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because hydrogen peroxide is indeed used in the Kastle-Meyer test, making it a correct application.
**Option B:** This option is incorrect because hydrogen peroxide is also used in the phenolphthalein hemochromogen test, which is another chemical test for blood.
**Option C:** This option is incorrect because hydrogen peroxide is used in the leucomalachite green test, which is a sensitive method for detecting bloodstains.

**Clinical Pearl / High-Yield Fact**
When using chemical tests for blood, it's essential to note that hydrogen peroxide can also react with other substances, such as peroxidase-positive bacteria, resulting in false-positive test results. Therefore, it's crucial to interpret test results in conjunction with clinical findings and other diagnostic methods.

**Correct Answer:** D.