Case Study#6   1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16   Special Coag Studies Polybrene added to plasma for PT and PTT with no shortening of clotting times. Interpretation: no evidence of heparin contamination Mixing study (1:1 v/v) performed using normal control plasma   Mixing Study Principles   Mixing Study Results   PT PTT   65.5 s 72.0 s     12.8 s 28.9 s Interpretation : factor deficiency affecting both the PT and PTT Breakpoint #4 What is your differential diagnosis at this point? What additional laboratory studies do you want? Do you need the results before treatment is begun? What treatment?