The complement system is a long and complicated event of reactions where activation leads to cleavage of different factors and ends with either inflammation or cell lysis.     Recent studies have shown that the complement system and coagulation have some elements in common. Therefore in this study it was relevant to look at the inhibition of the complement system in two different whole blood analyses of coagulation activation, thromboelastography and impedance aggregometry. Thromboelastography, or TEG®, measures the clot forming properties of whole blood and the impedance aggregometry, or Multiplate®, measures platelets’ ability to adhere and aggregate to an electrode. Four different inhibitors where used: Eculizumab, C1 inhibitor, Compstatin and OMS721, which all inhibits different parts of the complement system.     The curves from Multiplate® was presented in standard deviation and the number of reduction, while the results from TEG® was presented in before and after added inhibitor in graphs.     In conclusion, impedance aggregometry show a more specific and secure results of the inhibitors effect, which was seen by that both C1 inihibitor and Compstatin had a major influence on the area under the curve (AUC). In TEG® there were no detectable difference, which could mean TEG® is not specific enough for platelets efficiency, which is affected by the complement inhibition.