The stain used for demonstrating Auer rods in blasts is –
**Core Concept**
The identification of Auer rods in blasts is crucial for diagnosing acute myeloid leukemia (AML). Auer rods are needle-like azurophilic granules found in the cytoplasm of myeloid blasts, and their presence is a hallmark of AML.
**Why the Correct Answer is Right**
The correct answer is Wright's stain, which is a type of Romanowsky stain used in hematology for staining blood films. Wright's stain is particularly effective in highlighting Auer rods due to its ability to differentiate between azurophilic and specific granules in myeloid cells. The stain works by binding to the nucleic acids in the cell, causing the azurophilic granules, including Auer rods, to appear bright red or pink against a blue-purple background.
**Why Each Wrong Option is Incorrect**
* **Option A:** Giemsa stain is a type of Romanowsky stain but is not as effective in highlighting Auer rods as Wright's stain. Giemsa stain is commonly used for staining parasites and is not the preferred choice for identifying Auer rods.
* **Option B:** May-Grünwald-Giemsa stain is an adaptation of the Giemsa stain and is used for staining blood films, but it is not the best choice for demonstrating Auer rods.
* **Option C:** Hematoxylin and eosin (H&E) stain is a general-purpose stain used in histopathology and is not specific for highlighting Auer rods.
**Clinical Pearl / High-Yield Fact**
Auer rods are a key diagnostic feature of AML, and their presence can help differentiate AML from acute lymphoblastic leukemia (ALL). It's essential to look for Auer rods in blasts when examining a blood film or bone marrow aspirate.
**Correct Answer: D. Wright's stain**