A positive result shows granularity ranging from brownish-black to reddish-brown .

Flow cytometry (CD markers) and next-generation sequencing are more specific and quantitative. So why teach ?

Use a “traffic light / toolbox” graphic.

| Feature | Cytochemistry | Flow Cytometry | |---------|---------------|----------------| | Speed | 1-2 hours | 30 min | | Requires live cells | No (fixed) | Yes | | Antigen density info | No | Yes | | Cost | Cheap | Expensive | | Still used? | Yes – developing world, APL screening, TRAP stain | Gold standard for lineage |

SBB mirrors MPO closely but is slightly more sensitive for identifying early myeloid precursors. Like MPO, it is positive in AML. 3. Periodic Acid-Schiff (PAS) What it detects: Glycogen and related mucosubstances. The Result: Bright pink or magenta staining.