HematopathologyHematology

Mpo Stain

Normal Range
Positive in myeloid cells; Negative in lymphoid cells
Sample Type
Bone Marrow Aspirate / Blood Smear
Fasting
No
Unit
Qualitative/Percentage

Function

The Myeloperoxidase (MPO) Stain is a cytochemical test used to detect the enzyme myeloperoxidase, which is primarily found in the primary granules of myeloid cells (neutrophils, monocytes, and their precursors). It is a gold-standard tool in the microscopic differentiation of immature blood cells.

Why it is Ordered

This test is critically important when a patient is suspected of having acute leukemia. It helps hematopathologists distinguish between Acute Myeloid Leukemia (AML) and Acute Lymphoblastic Leukemia (ALL). Since the treatment protocols for AML and ALL are vastly different, an accurate MPO stain result is essential for choosing the correct chemotherapy regimen.

Associated Conditions

  • Acute Myeloid Leukemia (AML): Most AML subtypes (M1, M2, M3, M4) show strong MPO positivity.
  • Acute Lymphoblastic Leukemia (ALL): Characteristically MPO-negative.
  • Myelodysplastic Syndromes (MDS): May show varying degrees of MPO activity.
  • Congenital MPO Deficiency: A rare condition where cells lack the enzyme, potentially leading to increased infection risk.

Why Context Matters

MPO staining intensity can fade if the slides are not processed promptly or if the sample is old. Furthermore, 'lineage infidelity' in certain leukemias can cause atypical staining patterns where lymphoid cells express myeloid markers. A second opinion from a specialized hematopathologist and correlation with Flow Cytometry and Cytogenetics is often required for a definitive diagnosis.

Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.

Clinical References

Source-of-truth databases and clinical guidelines for Mpo Stain:

Research & Guidelines

Related Indicators

DR

Medically Reviewed by Dr. Binoy Babu, MBBS

Board Certified Doctor • 10+ Years Clinical Experience

Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.

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