Ho et al listed criteria for thrombotic microangiopathy (TAM) following a hematopoietic stem cell transplant. The authors are from the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Toxicity Committee.


Features of thrombotic microangiopathy following stem cell transplant:

(1) schistocytosis (more than 2 schistocytes per oil field in the peripheral blood)

(2) increase in serum LDH without other explanation

(3) concurrent renal and/or neurologic dysfunction without other explanation

(4) negative direct and indirect antiglobulin test results



• The number of schistocytes is per "high power field". This could refer to either the 40x high dry objective or the 80-100x oil immersion lens. An oil immersion field makes per sense since 2 would be around 1% if the smear near the feathered edge is examined.

• Renal dysfunction is indicated by a 50% decrease in the creatinine clearance from baseline or a doubling of the serum creatinine from the hospital admission value.


Ccalcineurin inhibitors should be withdrawn once TA-TMA is diagnosed. Plasma exchange has not been proven to be effective.


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