A rare and devastating family of disorders, TMAs are characterized by thrombi or clumps of aggregated platelets in small blood vessels, which lead to thrombocytopenia (below-normal platelet counts) and schistocytes
(fragmentation in red blood cells) that can cause dangerously low oxygen levels in organs like the brain and kidney as well as anemia.
This combination indicates that the technologist should confirm a low PLT count and the possible presence of schistocytes
on the peripheral smear.
The presence of schistocytes
on the peripheral blood smear, elevated plasma lactic dehydrogenase, and decreased haptoglobin concentration are used as evidence of microangiopathic hemolytic anemia to make a diagnosis of TTP.
The peripheral blood smear can show up to 10% schistocytes
, along with helmet cells, which are produced due to damage of the endothelial layer of small vessels, resulting in fibrin deposition and platelet aggregation.
The blood film showed schistocytes
and fragmented red cells and a diagnosis of TTP was first considered.
Therefore, TAM should be defined according to the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Toxicity Committee of the American Society of Blood and Marrow Transplantation (ASBMT) as follows: (1) RBC fragmentation and [greater than or equal to] 2 schistocytes
per high-power field on peripheral blood smear, (2) concurrent increased serum LDH levels above institutional baseline, (3) concurrent renal (doubling of serum creatinine compared to the value before hydration and conditioning) and/or neurological dysfunction without other explanation, and (4) negative direct and indirect Coombs test results .
Intravascular hemolysis is diagnosed with laboratory studies that show anemia, low haptoglobin, elevated lactate dehydrogenase, and blood smear schistocytes
2,3) As most TTP patients do not display all five criteria at presentation, the combination of thrombocytopenia, anemia, and the presence of schistocytes
on the blood smear must often be presumed to be due to TTP if other causes of such findings, such as DIC or the HELLP syndrome, can be clinically excluded.
3%; platelet count of 30 pL; schistocytes
on the blood smear; total bilirubin of 14.
Review of peripheral blood smear revealed markedly increased eosinophils and 4+ schistocytes
on a peripheral blood smear indicate microangiopathic hemolysis.
Nonspecific red blood cell abnormalities can be present, such as anisocytosis, poikilocytosis, anisochromia, basophilic stippling, schistocytes
, and erythrocytes that are poorly hemoglobinized.