Leukocyte alkaline phosphatase

Normal values:

staining score 20 to 100 (out of a maximum of 400)

What abnormal results mean:

LAP is usually increased with:

• polycythemia vera
• myelofibrosis

LAP may be normal or increased with:

• leukemoid reaction to infection
• women on oral contraceptives

LAP is usually decreased with:

• chronic granulocytic leukemia

LAP may be decreased with decreased bone marrow activity:

• pernicious anemia
• aplastic anemia
• thrombocytopenia

LAP may be decreased with:

• paroxysmal nocturnal hemoglobinuria
• infectious mononucleosis

Additional conditions under which the test may be performed:

• primary thrombocythemia