23220:LEUKOCYTE ALKALINE PHOSPHATASE (LAP) STAIN

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23220:LEUKOCYTE ALKALINE PHOSPHATASE (LAP) STAIN
Alias Names: LAP STAIN
Methodology: Cytochemical staining with microscopic scoring of stained slides
Edit Date: 7/8/2009
Performed: Daily
Released: 24 hours
CPT Code: 85540
Specimen Collection Details
Collection: One 4 mL green top tube (heparin). Immediately prepare 4 blood films, unstained and unfixed).
Handling: Protect tube and blood films from light by wrapping the tube in foil and sending slides in slide folders. Do not refrigerate blood. Send to the laboratory within 24 hours.
Stability: If protected from light, blood stable 24 hours ambient and slides stable 5 days ambient.
Standard Volume: 3 mL heparin whole blood AND 4 slides.
Minimum Volume: 0.5 mL heparin whole blood AND 1 slide.
Transport: Ambient, protected from light.
Comments: The LAP stain is useful to distinguish between neutrophilia due to infection (elevated LAP) and neutrophilia due to chronic granulocytic leukemia (decreased LAP score). Other causes of low LAP scores exist, notably paroxysmal nocturnal hemoglobinuria (PNH).
Rejection Criteria: Exposure to light; blood more than 24 hours and slides more than 5 days after collection.

40-130 LAP score.