Myeloperoxidase (Mpo) Stain

Myeloperoxidase (MPO) Stain

What it is

The Myeloperoxidase (MPO) stain is a special cytochemical staining technique used on blood or bone marrow smears to detect the enzyme myeloperoxidase within myeloid cells. Myeloperoxidase is an important marker of granulocytic differentiation, and this stain helps to distinguish between acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). It provides a rapid and inexpensive method to assess myeloid lineage in hematological disorders.

Uses

This stain is mainly used in hematology to support the diagnosis and classification of acute leukemias. A positive MPO stain confirms myeloid lineage, making it an important tool in differentiating AML from ALL. It is often performed alongside other cytochemical stains and immunophenotyping for a complete diagnostic picture.

Symptoms That May Lead to the Test

Doctors may recommend this test if you present with symptoms suggestive of leukemia or bone marrow disease, such as persistent fatigue, recurrent infections, unexplained bruising or bleeding, enlarged lymph nodes, fever, night sweats, or abnormal blood counts.

Abnormal Results

Positive MPO Staining: Indicates myeloid lineage involvement, strongly supporting a diagnosis of acute myeloid leukemia (AML). The intensity and distribution of staining can provide additional diagnostic insights.

Negative MPO Staining: Suggests lymphoid lineage (e.g., acute lymphoblastic leukemia) or non-myeloid disorders. However, interpretation must be combined with morphology, flow cytometry, and other tests.

Risks

The MPO stain itself carries no risks, as it is performed on collected blood or bone marrow samples. Risks are limited to the sample collection procedure, such as minor bruising, pain, or dizziness from venipuncture, or soreness from bone marrow aspiration. These effects are usually mild and temporary.