WHAT IS TARTRATE-RESISTANT ACID PHOSPHATASE (TRAP) STAIN TEST?
Tartrate-resistant acid phosphatase (TRAP) is an enzyme produced by osteoclasts and contained in hairy cells. The presence of tartrate resistance to acid phosphatase is diagnostic for hairy cell leukaemia (leukemic reticuloendotheliosis), a chronic form of leukaemia characterized by distinctive cells called “hairy cells,” which have many fine, cytoplasmic projections. Thus, this test is used to help diagnose hairy cell leukaemia and assess response to treatment and is a marker for the rate of bone resorption. Newer research has found that TRAP is produced by some osteoclasts causing bone dysplasia. This test may be performed on bone marrow or blood. If bone marrow is positive for hairy cells, another confirmatory morphologic testing is needed because TRAP-positive specimens may be caused by conditions other than hairy cell leukaemia.