In These situations, tests of the ADAMTS-13 activity seem to be the most useful for the diagnosis in TTP. Fujimura and Matsumoto categorized TTP using plasma levels of ADAMTS13 activity (<3%; severe, 3–25%; moderate, 25–50%; mild) for the purpose of distinguishing TTP from TMA. They also reported that the levels of ADAMTS-13 activity are lower in idiopathic TTP than in secondary TTP [ 22 ] . Generally, patients with autoimmune diseases tended to a have mild-to-moderate deﬁciency in ADAMTS-13 activity. In addition, Coppo et al. reported that patients with severe ADAMTS-13 deﬁciency in adult idiopathic TMA are characterized by various autoimmune manifestations, a lower platelet count, and mild renal involvement [ 23 ] .
Several brands of IVIG have been approved by the Food and Drug Adminsitration (FDA) (see table in Appendix). There is a lack of reliable evidence that any one brand of IVIG is more effective than other brands. However, immune globulin products may differ from each other in ways that may be important in a particular patient. Different manufacturers then use various combinations of precipitation and/or chromatography steps to obtain a final preparation that consists of greater than 95 % IgG in all currently available products. The various manufacturers also use different final purification steps and stabilizers to obtain their final products, which may then vary in storage requirement and shelf life. In several currently available products, stabilizers include sugars, such as sucrose, glucose, or maltose. Other products contain amino acids such as glycine and proline. The sodium content of different products also varies.