Screening Test Abnormalities in Inherited and Acquired Coagulopathies
PT PTT Factors Inherited Acquired
VII FVII defic. Vit. K defic.; liver dis.; factor inhib.
VIII or IX Hemophilias, vWD Antiphospholipid Ab; factor inhib.
I, II, V or X Fbgn, FII or FV defic. DIC; liver dis.; factor inhib.

Further coagulation tests (JAMA 2016;316:2146)

  • Mixing study: useful if ↑ PT or PTT; mix Pt’s plasma 1:1 w/ normal plasma and retest
    • PT/PTT normalizes → factor deficiency; PT/PTT remains elevated → factor inhibitor
  • Coagulation factor levels: useful eficiency