Sepsis is a life-threatening organ disfunction, which is caused by a dysfunctional immuneresponse and develops when an infection overwhelms the body’s defense mechanism and causesand uncontrolled inflammatory response. Biomarkers have a great impact on helping diagnosisand treatments of sepsis. The biomarkers, like miRNA, are needed for both more accurate andquicker diagnosis of sepsis in patients. The future diagnostics are looking at other types ofbiomarkers, e.g. miRNA, but low amounts of miRNA are present in biofluids and make itchallenging to quantify. A new methodology is needed which is both accurate and does notrequire a lot of fluid. The aim of this project was to identify which kit of two kits and which oftwo volumes of plasma would lead to the highest concentration of miRNA and highest quality ofmiRNA extracted. This was quantified by using two different volumes, 100 μl and 200 μl, andextracting the two volumes with both exoRNeasy Serum/Plasma midi kit (Qiagen) and TotalRNA Purification kit (Norgen). There was no statistical difference between median miRNAconcentrations between the two volumes within the Qiagen kit. However, the mean miRNAconcentration (0.833 ng/μl) obtained from the Norgen kit (100 μl plasma starting volume) wasstatistically higher than the mean miRNA concentration (0.570 ng/μl) obtained from the samekit with 200 μl, p = 0.033. The optimal kit and volume of this study is the Norgen kit with 100 μl.Further studies are needed to verify these results.