Stains & CD markers
TRAP (Tartrate resistant acid phosphatase)


Last author update: 1 June 2005
Last staff update: 3 June 2022

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PubMed Search: Tartrate resistant acid phosphatase

Nat Pernick, M.D.
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Cite this page: Pernick N. TRAP (Tartrate resistant acid phosphatase). PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainstrap.html. Accessed August 11th, 2022.
Definition / general
  • 1 of 7 isoenzymes with different tissue distribution
  • TRAP is found in hairy cell leukemia; other acid phosphatases are found in red blood cells, prostate, white blood cell lysosomes
  • Sensitive and relatively specific for hairy cell leukemia when combined with DBA.44 positivity (Am J Surg Pathol 2005;29:474)
Positive staining - normal
  • B lymphocytes of marginal zone, osteoclasts
Positive staining - disease
  • Hairy cell leukemia, mantle cell lymphoma (57%), splenic marginal zone lymphoma (some), primary mediastinal B cell lymphoma (54%), CLL / SLL (41%), giant cells in giant cell tumor of bone and soft tissue (Hum Pathol 2005;36:945)
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