For patients with suspected complement-mediated TMA, are there specific clinical or laboratory parameters that can help guide the decision for starting empirical treatment (e.g., eculizumab) while awaiting the results of complement testing?  

I just want to point out that hemolytic microangiopathy (as seen on the peripheral smear by our Hematology colleague) is paramountly important in determining the presence of TMA. Laboratory parameters may be misleading. I have seen even ADAMT13 levels very low in sepsis and DIC process. Therefore lo...