Specific stain for myeloblasts is:: (A) Sudan black, (B) PAS, (C) Myeloperoxidase (MPO), (D) LAP
Answer is C. Lymphoblast: PAS positive.
Myeloblast: Sudan black, myeloperoxidase and non-specific esterase.

 “MPO is specific for myeloid differentiation. Sudan Black B reactivity is similar to MPO in myeloblasts and monoblasts. The specificity of Sudan Black is less than MPO.”